Enjoyed the video but the solutions advised of in the video fell far short what should have been the case. The real issue re the equipment in unconditioned space is that the build quality on most air handlers and ductwork are not designed for Florida and other high humidity areas. Since that is highly unlikely to change, go look at how the industrial community prevents condensation on pipes/equipment in areas where humidity cannot be controlled easily. Some solutions are a LOT less expensive than the initial and ongoning cost of a dehumidifer. That said the air obviously needs to be conditioned/dehumidified as is appropriate to prevent condensation on other components of the structure as well not just HAVC equipment! The goal of an HVAC technician SHOULD be to educate on what is needed to prevent/control unnecessary moisture damage to all structural components not just in the primary occupied space and the components that do the conditoning. Obviously some of those other solutions will require referals out. A follow up video on a complete list of realistic solutions (as opposed to ripping out insulation/heat barriers SMH) is appreciated for those that seem to struggle with recognizing solutions on their own.
My dude, I've loved all your videos till this one. Insulating ductwork definitely works just like putting my beer can in a coozie keeps the sweat ring off the table. Doesn't matter if it's internally or externally insulated it still works (I'm in Texas). In a home, sweating vents are usually because the return air to the handler has been compromised and the evaporator is sucking in wet attic air (in Texas it tends to be installed in the attic). Re sealing tends to do the trick. Keep up the great work and mostly love your videos.
@@williamkorver9856 To put a dehumidifier in the attic which supposed to be vented to cool of the shingles and keep heat gains low... what a halfwit. No wonder the students couldn't answer his questions.
I watch your videos NOT because I am an HVAC guy, but just a homeowner who wants a good understanding about my system and how it should be serviced and maintained.
My air handler unit is in the garage and it was sweating like crazy all the time (FL-Southeastern) until I bought a dehumidifier and placed it in my living room. It runs about 1 hour everyday keeping my humidity below 40%. I haven't seen a drop of water again around the air handler since then. Its perfectly dry all the time. This channel is awesome. Thank you
Is this method still working for you during this extremely hot and humid 2023 FL summer? It’s so humid rt now and just started leaking for the first time from my AHU, which is also in the garage. AC unit is almost 2 years young, that makes a difference. I would have never thought to put the dehumidifier in the living room. Very curious if is this is still working for you right now. Will likely be trying either way at this point though. Thanks
Yes, it’s working really well. My humidity is around 32-34% all the time. Now, there is something else I learned, blower speed. For some reason my blower speed was really low. It’s called CFM. It was low but not to the point of freezing the evaporator but it did an excellent job dehumidifying it too. Another factor is the thermostat setting. if its too low (72 F), you can get I lot of condensation. So, it’s a lot of small details that increases this condensation in my garage AC units. Good luck, keep searching
@@MichaelHernandez-lc2wb thank you! I actually got a wet/dry vac and used vinagre to suck out a bunch of shit that collected from last year. Apparently my sis didn’t know to do this monthly…. Worked right away and dried up leak going down garage… granted here ac unit is less than 2 years old. So if anyone reading this has tried this and has cleared the line, I suggested calling a tech for sure!
My wire-tap phone must have been listening again and recommended this video. I am experiencing all the problems described here and my HVAC guy couldn't figure out in 4 days what you solved in minutes. He even had me put in powered attic vents which are drawing in more swampy air.
6:51 -We use this concept in refrigeration by installing mullion heaters in the door frames to increase the temperature to above the dew point of the surface of the door facing.
Been dealing with a customer for the entire year asked multiple old timers and non of them solved the issue like you did today thanks I feel like a took agigant elephant off my back
Top of the line advice...don't b afraid giving the customers solutions" without thinking about their expense and decisions...lots of techs are afraid to do it...
I really enjoyed your class. A much needed class. I had my Coils Cleaned. This was necessary. My workers didn't sanitized my Coils after. This lead to a stink, causing me to replace Air FILTER/s. Then I called in a H-vac Company, and I told them as I wrote you, it's stinks and I'm using much more AIr Filter/s than needed. Now I was having my Coils Sanitized, and cleaned my motor, which was growing mold. This was just for a Vent Cleaning. Look where it ended? Now, I feel cold from my vents. Having a Duct Tape Smell. I don't have any leaks, great, but why does my apartment smell like trash? In Summer months the A/C will never stop running with this problem now. I really need an understanding why I smell cigar smells. I never did before. Another weird matter, FL, it's 73 degrees, my unit is on 78, why would my unit go on at this degree? I had to raise my Thermostat to 79. This is a problem. What, I don't know. Any suggestions?
Put the air handler in the home's envelope. Equipment, Supply Duct and Return Duct should never be outside the envelope. If energy conservation were paramount, Energy Star, DOE ect would make building code require equipment to be located inside the home. No one wants to give up 12-14 sq foot of foot print. OSHA should require this also, I've been in 130-150 degree attics, not a safe condition.
I agree 120%!! So many people want another closet to cram with junk instead of putting the A/H in there. Lasts longer, maintaining it happens more frequently, doesn't sweat, and I'm sure much more. What do you gain by putting it in the attic....a spot to store junk....thats it.
@@thomasnew8606 We average about 4 new homes a week, live in Kansas, 99 percent have basements. Good place for HVAC duct and a place to go during tornado season. Also adds extra living space. Attics are terrible places for HVAC., We do a couple new home attic installs a month. Have to increase size of A/C to accommodate attic heat.
@@skikansas66617 very few homes in Texas have a basement as it adds a ton of cost to a home build that’s not needed. An conditioned attic is just fine to run the hvac but few homes have that as well it seems.
@@thomasnew8606 ...Same in SC.....but the point is still valid. Place the Air handler and system in the conditioned-space. Hard to do, as SC is one of a few places where one can buy new, SMALL homes...and most of these are built on-slab. I get it, you can give up some living space but its a tough market for this design change to take root.
Have been a fan of your teaching methods, there are many channels which put light on the subject, but the way you describe things, it's just so simple and easy to grasp. Keep up the good work.
If you have metal registers that are sweating try installing plastic registers and sealing around them to keep warm/humid attic air from leaking around the ceiling opening.
This video came to me at the perfect time. I’m going to a customers house to finish an air handler and condenser install, but also the vents in two of her rooms are sweaty and my boss wants me to put foam tape on the backside of the air tech registers to seal it from the attic air.
Slight counterpoint...... in the South where I live, air handlers are located in attic that ( as they normally are built today) are vented attics, yet run very hot in the summer. The air handler has the evap coil inside which produces the cold air that gets sent to the home's "conditioned -space" via the ductwork attached to the air handler.. BUT...if the air handler cabinet has poor insulation, as is often the case, the interior cold surface temps of the air handler cabinet.... migrates ( conducts), to the outer-surface of the air-handler cabinet. The outside then gets cold enough to condense the hot-humid "atmospheric" air found in the attic. In this case....it is indeed the addition of MORE insulation onto the exterior air-handler cabinet.....to minimize the cold temp migration affect from the inside, that can help. After adding a suitable amount of insulation to the outside surface of the air handler cabinet...it's exterior will be "less-cold" ( warmer) on its outside surface.....and if done enough....won't have the exterior temp be so cold as to go below the attic-air dewpoint. Here is one example where adding insulation does work.........the same argument can be applied to additional insulation wrap on the insulated ductwork that snakes around the exposed areas of such an attic. All correct.....right?
I wish that question would have been answered. I too think proper insulation around the ductwork would prevent sweating. I just had a new Trane HVAC system installed in my crawlspace replacing a 20 year old system. I had all the ductwork replaced using steel ducting for the trunk line and returns. The system was installed in April 2024. I went under the house yesterday to replace the filter. I was shocked to see water droplets all over the trunk line. The feeds to the registers were fine. I believe the contractor used too light of an insulation around the trunk line. I called them today and asked what would you have done if the trunk line ran through the attic. He said we would have used R8 wrapping. He said in a crawlspace the code doesn't call for that. I said, if I would have known that I would have paid extra for R8. Now I am concerned I will have a black mold problem if I don't remedy the sweating.
@@tiger859986 ...basic thermodynamics....and citing "Code" for not doing something that is technically sound and professional.... is a crutch. Try having him see this point or maybe then only court actions may work for unprofessional work that can cause health issues? Aside.....the factory manual for my air handler specifically identifies that additional insulation may be required to encapsulate the air-handler in the attic ( even though a thin layer of insulation is factory installed on the interior surfaces).
@@tiger859986R-8 insulated ducts in crawlspaces still have exterior surface temperatures below the dew point in a typical humid climate crawlspace. As stated, effective countermeasures include raising the temperature of the environment and/or removing humidity from the environment, neither of which is practical in a ventilated crawlspace. Adding duct insulation isn't likely to increase the surface temp of that duct enough to get it above dew point. Encapsulate the crawlspace
Hi. My air handler is in my garage and it’s sweating and black mold keeps ground around the white mastic at the top and mold is growing where the insulated pipes go through the ceiling above it. Do you think the pipe might not be insulated properly above the ceiling? Also how can I prevent the mold from growing on my air handler?
@@MosesDaverman_Realtor ...I'm not there to see the specifics but in general mold occurs in the presence of water and maybe a temp difference.....you have to open things up and remove the mold.... Borax usually works well, ( no bleach)...or Zinzzer special paint over the area afterwards? Then, yes....go after why it happened in the first place, like additional insulation with a vapor barrier.
Fantastic! I felt like I was watching Abbott & Costello announce the starting lineup beginning with "Who's on First Base?"! Condensation! Dewpoint! Humidity! Saturation! Great educational video! I just wish I could help my parent's HVAC and Home Repair Issues! We live in the original "Redneck Riviera" of Florida. I am going crazy trying to find Craftsman and Experts in any field - it seems as though most are Grifters and that the Grifters get more support from the Florida State Government instead of the Property Owners! I do not know where to begin ---> the state government and the insurance industry forced us to get a new roof! Now the state of Florida is demanding new roofs every 10-to15 years! We had 10-years of life remaining on the roof that my parents had installed in 2004!
Professor Ward recommendation is dehumidifier in the attic with Harvard loop on the suction line and all duct work with the Adamek bend. Customer Ward wears his cap and gown on all service calls
@@JaimeBlanco666 it should be vapor tight - insulation at least 2" covered with aluminum foil sealed everywhere with aluminum tape . This way no water vapor will get inside and condensate.
@@grigorshukerski4689 and what about when your AHU itself is sweating? This video didn’t spout nonsense. I just think you don’t quite understand dehumidification.
Great. My agency has been involved with the Weatherization program for half a century. We've gone from plastic over windows to geothermal and solar. Some of the biggest issues we have dealt with (I'm from Oklahoma and only Fla and OK know what real humidity is....Ha) is sweating vents. These are full new HVAC install to upgrades, insulation, attic sealing and air flow and on and on. I'm now 68 and retiring. I've seen it all from retrofit (toss storm windows and blow insulation) to dealing the Lead based paint. I've always felt bad for my crews. Anyway, I have a nice house built in the 70's. Cathedral ceilings and High efficiency (seer) HAVAC. This is the first year one of my vents in the ceiling of living room has started to drip. It's has the cathedral ceiling where this drip from the vent is. It gathers on the outside of the vent till it hs enough moisture to drop a drip. Temps were at or over 100 with Humidity of about 40%. My vents are all wrapped and sealed with insulation and R21 blown. We had a ridge vents installed with the last new roof for better High Low venting. What can I do to stop this one vent from dripping. Help
The attic dew point does not change when you change the temperature. Condensation forms when the duct surface temperature is colder than dewpoint. However, warmer attics will warm up the an uninsulated duct surface a bit so I could see how it reduces condensation.
This was a super helpful video for me. I Installed an exhaust vent from our OTR microwave in our kitchen up through the ceiling, attic, and capped it off on the roof. Very short run (less than 4 feet) since it's 1-story home and the range is close to an exterior wall (6" round straight duct). Temperatures today were 102 F with a dewpoint of 79 F (51% humidity). I ran the hood vent (new fancy schmancy OTR microwave, strong exhaust fan) after heating up some food and went about my business. Left the fan on for less than 10 minutes. I go back in the kitchen an hour or so later and hear water dripping and see water slowly dripping from the side of the OTR microwave where it meets the cabinets. I look up above the OTR microwave at the duct that is inside the house and see it sweating quite a bit. So I'm all worried about if this is a new issue or one that's been happening for awhile and start researching. I figure I need to insulate the duct before I better seal the gap between the duct and the ceiling (which definitely allows warm attic air in). Well your video perfectly explained the issue for me and has saved me from making the mistake of reaching for insulation instead of just focusing on sealing. And you've also calmed my worries about the portion of the duct in the attic since, as you said, air moving through the duct does very little to the duct's external surface temperature. Only annoying part for me is that the duct goes from the OTR microwave through the tiny cabinet above the microwave, and then through a like 4" tall space between the top of the cabinet and the actual ceiling, and then finally into the attic. I can easily seal up the gap between the inside of the cabinet and the space between the top of the cabinet and the ceiling. But there's no easy way for me to seal the gap between the actual ceiling and the attic (but luckily that hole/gap is muchhhh tighter, albeit not tight enough given the warm air that can be felt rushing in to replace the air exhausted out). I'll probably just have to seal it up from within the attic even though it's too cramped to even crouch at the point where the duct is 😅.
I'm a HVAC tech like most of us here. I personally had sweating vents in my 2nd floor system ( hvac in attic) . I found the original hvac contractor had not sealed the boots off the ducts right around the sheetrock and the boots were poorly insulated. Some had no insulation on the boot. The moist hot attic air was coming around the boot , gaps ( 1" or more ) mixing right at the diffuser face. So very cold and very moist hot air cause vents to condense on the face. Everyone of them were like this. I end up pulling every boot and redoing some of the runs completely. Everything was sealed tight from the condition space and boots were properly insulated . No more sweating vents....
I think this sounds like it very well might be my issue. I have only one vent that has a sweating problem (and it happens to be right above the air handler so I was the dummy thinking the air was colder and that was why). I have no attic access and the vent is 15ft or so up so not the easiest to get at. Any suggestions for a quick fix?
@@ByteHeisenNerd you can pull the diffuser off ( supply vent ) some installers would nail the boot from inside on a roof rafters or a nailer cause they don't have a lot of room above to work since there is no attic. If you find that they are nailed on inside you can pull the nails to free the boot. Then you can maneuver it around in the ceiling to put small pieces of insulation. This will be a royal PITA cause it won't allow for a lot of room. Reinstall the boot by nailing back tight. Use caulk to boot tight to the sheet rack and reinstall diffuser.
@@ByteHeisenNerd if there is no way to remove boot from below then you will need to square up a section of sheet rock you want to remove. If it I was doing i would cut a 2'x rafters bay width ( 2'x16" or 2'x24" ) piece of rock out. This would allow you more then enough room to put nailer ( scab pieces of wood ) back in for your sheet rock seems and room to insulated the boot.
@@pineychristian thanks so much for the reply! I appreciate all the detailed explanation. I will make my way up and try option 1 first, then cut back the rock if it’s not possible. Thanks again!
My air handler inside home. I insulated drain pan with armaflex, 1/4" steel drip pan under that, cork under drip pan. Walls pour foamed that air handler is in. Coil room insulated on inside with armaflex. All duct solid steel, air sealed 100%. All ducts insulated with bioceramic r7 (hy tech) paint then insulated with reflectix, no gaps anywhere. Positive pressure condensation drain with skupper valve. 4" fresh air intake triple filtered, shut down in extreme temps. Ecm main fan and ecm fresh air fan. 6 uv lights surrounding coil set to timer. Crawlspace partially conditioned with temp and humidistat. If you have more than 10% diff you will reach dewpoint from what i understand. House is confortable. All walls, subfloors painted with insulating ceramic paint (hy tech) with concrobium and zinser paint. You are right you need to lower humidity in home to prevent condensation or keep the variation of temps below dewpoint. Btw bath walls do not sweat ever, only windows. Bath fans set with auto humidistats. All wall and ceiling and floor protrusions sealed 100%
I had my attic spray foamed and they would not do so without removing the insulation. They said it would allow condensation on the ceiling drywall and grow mold/ mildew. The attic is way cooler, considered conditioned space. Luckily our humidity near Dallas Texas, we haven't had any condensating ducts or vents.
I think the issue is that most people care more about lower power bills than some black mold on the outside of ducts in an unconditioned attic. A conditioned attic space, so all the ducts run in the conditioned space, is the best solution... for new construction. I hope all local codes are moving to enforce this. Put everything inside the conditioned envelope.
Really great teaching session. Bryan knows his stuff. It is scary and unfortunate that the students in this class are not committed to understanding the profession they are trying to work in. After this the client calls them for service, it looks good but lots of problems because these tech's don't know what they are doing well enough to provide successful outcome but all good and well enough to be certified. As an industry professional I find this most unfortunate.
Thanks for the video. I'm having sweating problems with a portion of ductwork in the basement that has been finished/boxed over with drywall. Small amounts of water are coming through a ceiling vent and portion of the wall in the finished bathroom in the basement. Also, I have paneling on a wall (on the other side of the basement bath) that is below the return and on the outside wall that is warping from the sweating ductwork. So, what's the issue? I'm already running a room dehumidifier in the basement. With that, the relative humidity stays in the 50/55% range. Should I check for an infiltration problem on the outside wall of the house? Should I raise the temp that we run the AC at (currently 74 degrees for the house with the basement temps around 70 degrees)? Before I start tearing down walls and the ductwork boxes it would be good to have some idea what the cause of the problem might be. Thanks to anyone who might have some insights. In the end, if I can't figure it out, I'll try to get an HVAC guy in who hopefully knows what they're talking about.
I dont think the solutions in this video could be the best. Obviously if you dehumidify the space around the ductwork you are not going to have trouble with ducts sweeting, but I think is not practical. I think the best solutions is a good insulation in the ductwork, if you insulated the ductwork, the external temperature of the duct is going to be above the dew point and the ducts are not going to sweet. Same thing with the air handler unit. The best way to avoid this problem is selecting the right equipment in the beginning of the project. This could be a solution if it is too late and anything else solves the problem.
hi, very informative. thank you. what humidifier for attic you recommend ? I have a 20 year old house that has pink fiberglass on the floor of my attic. my house is 3500 sf and my attic is very humid as I live in south florida
Some interesting info. One point of correction is moisture moves by vapor pressure not air pressure (airflow). air curtains don't keep moisture out. Doors only help if they are sealed. Kitchen pressurization only reduced infiltratration or fresh air. You still need vapor barriers to keep moisture from migrating in and out of buildings
It doesn't make any sense to increase heat gains just because the ducts are sweating. It is like killing a fly with a cannon. People are talking about zero loses/gains houses nowadays. Just insulate your ducts well enough,so the surface will be above dew point and seal with vapor barrier ( the ducts, not the attic). Condensation on the vents can be solved by mixing the air leaving the evaporator with additional amount of air from the house in a such a way so the air exiting the vents is above dew point ( more air flow with temperature just above the dew point).
Not sure why adequate insulation with an appropriate vapor barrier would not keep moist air from condensation on the ductwork. This is the approach in most mechanical rooms.
If you have a supply grill in a vaulted ceiling and its sealed and insulated perfectly but sweating put a curved blade register and it will cool the area near the sweating register done it many time after other company tried everything works every time. If you have sweating spiral duct in a restaurant and its dripping on the customers all you have to do is direct the air up instead of vertical or down then the area around the sweating duct work will be cooled down and no more sweating. If you have sweating equipment in an attic unvent the attic and seal the attic then put a small portable dehumidifier in the attic problem solved.
I live on the Gulf coast. Fifty years ago we didn't ventilate our attics and they would get to 140° or higher in the middle of summer. It would take all night for that temperature to come down to dew point. By that time, the sun had come back up and reheated the attic and we had zero sweating problems. Fast forward to today and with ridge vents, soffit vents, whirly birds, powered fans, white metal roofs etc, attics don't get anywhere near that temp. If it's 100% humidity outside and your attic is ventilated, it's also 100% humidity in your attic. Add more efficient equipment and variable fan speeds and the air temps in ducts make it almost impossible to stop the sweating especially on older systems that still have R4 wrap. People hate to hear it but I tell everyone to stop up all the ventilation, dehumidify the attic for a few days and put R30 on the ceiling. Shingled roofs don't last as long when it's that hot in the attic but at least it isn't raining on your ceilings. Been doing that with some success for fifteen years or so. I wish I would have seen this video decades ago, was a lot of trial and error figuring this out. 😂
Gulf Coast Wisdom. Similar in GA, but less stringent. Humidity can manage itself if you do not over-design a system or over-ventilate; that hot attic is your friend here in GA, too, to a point (110F is fine).
In SWFL, was told we needed a new 4 ton. Purchased 4 ton from them, they installed it in attic, less than a year later and its dripping into our ceiling and find out they installed a 5 ton air handler, but kept fan speed at stock (guess it can be reduced to medium to act like a 4 ton?). Anyway, terrible sweating on unit that is causing water damage to closet/ceiling below it. They are blaming our older ductwork that they said is too small/old, but didnt say it was an issue before and obviously they installed things incorrectly from the start. Very frustrating so far.
Ohio We Get Dewpoints over 70 fairly often Duct work in Basement was getting Damp. Put in a 6" Round to the Return Air and Angled it such that the Air flow in the return helped induce some air flow @ the Furnace Blower. The other end is vented outside. Thru an ole Coal Scuttle (They Make Special Vents for this) The Scuttle just conceals that it even exist. My Unit is Slightly undersized from before the addition's 4T (Load Calc says I need ) 4.5-5T so it tends to have long run times. Before I needed to set the Thermostat at 70-72 to be Comfortable Now I have to wear my Fuzzy Robe at 75-76 because it dries out the air so well. I do on Occasion hit the times when it is "Muggy" outside and Coolish (Mid 70's) that I need to bump the Temperature down a bit. Duct Work stays dry. Slight Positive pressure on the house when the AC (Fan) is running Reduces Humidity infiltration. That is I believe why it is cold at 75 when it is hot/humid outside and I need to turn down to 72 when it is cooler and Muggy outside.
High humidity air hits the surface with temperature below the dew point will result in water. To stop the water, you need either high temperature or low humidity. High temperature means more energy cost in winter. So I would think a good seal + dehumidifier would be the solution.
So is caulking around the ceiling air vent a good idea if the vents are discolored? i.e.remove the air cover and calk between the ceiling drywall and the air duct?
I had this problem in my first place over 15 years ago. Instead of all those expensive and complicated solutions I just replaced all vents with plastic vests. Problem solved. Not sure last time I looked for them it was harder to find.
I live in NJ and on very hot humid days above 90 2 of my 6 ceiling vents sweat. Sometimes sweat enough to drip on floor. It has damaged the drywall on ceiling around the vent. The unit is 20 years old seems to run ok and comes on and off throught out the day to keep 76-78. I have no attic space I live on top floor in a condo with vaulted ceilings. What can I have done that wont have me throwing money away when I call a hvac company. My unit has never been serviced since ive moved here 16 years ago. I change filters 1 time a month and always have
Air duct that runs from basement up to first and second floor all behind a laundry shoot. Only accessible from basement level. Lots of sweating and moisture collecting at bottom of the basement floor in laundry shoot. It seems to only be insulated for about the height up to the first floor. The insulation is completely saturated and dripping. We just redid our kitchen on first floor and opened up the wall for some plumbing changes and it also allowed access to that ductwork. And our contractor just wrapped about 8 more feet of ducting with regular wall insulation batts and now the wall is sealed up. What do i need to do? Trying to learn anything i can before hvac tech comes out so i have some idea what to expect
Usually after days of rain we get these calls, condensate pumps run more, moisture appears on ducts and supplies and the accusations the system is not working. I always ask what modifications were made to construction before this issue..some have an answer, some don't but regardless, the problem exists now and hopefully options are on the table. Sometimes the owner will have blueprints of the new work that could help find where the moisture ladened air is infiltrating the conditioned spaces. .what a job we techs and contractors have .
Good job 👍😎 I have a problem on a closet I’m going to tomorrow. Duck is sweating. Only in that room. I think the air is too slow to that closet in that closet gets very hot for some reason. It has an adjacent attic on one side and it also has an attic above and behind it has a call wall on a condition space 72°. This area had just recently been done a couple years ago when they found mold in there on the walls and near the ceiling. That wasn’t just the other area there were some other spots as well. The house has three infinity systems. Currently there is only one duct sweating. More will be revealed tomorrow when I check on it again. Attic is very hot and 71° upstairs as well. I told him to try 73°
Increase the superheat on your air con. Dehumify and reduces cooling capacity. Stops the issue of cold and humid room. I used to use 2.4kw heater in humid summer untill i discovered 10 deg superheat on cool mode fixes this. Stops mouldy ceiling vents too
Two new vertical air handlers were installed in ground floor commercial bldg unit. Air handlers are in closet, next to a room in conditioned space. The door between room and closet is not sealed, and it has a vents built into the door. Vent "fins" are stationary and angled down on the adjacent room side. The installers cut into the cold air sheet duct above each Air Handler and added louvered vents. Now the closet with the air handlers is a conditioned space and ducts are sweating and dripping. Seems to me this is not a correct installation. Climate Zone 6B
What about doing double wall ducts so the outside temperature is closer to the ambient temperature and the inside can fluctuate? Just like the windows?
I had the same problem with 2 rooms in my house and they HVAC people who installed it could not figure out why. They put in another return (I think). Initially no sweating but returned. If U remember right what solved the problem was dehumidifying to 40%. Which this video was available when I was looking for a solution 2 years ago.
I have a question, wouldn't insulating/sealing the ducts better and insulating the outside of the air handler also solve the problem because by doing so you are increasing the temperature of the surfaces of the ducts/airhandler. In theory you could just increase the amount of insulating material until the surface temperature is close to that of the attic?
@@madzmadeit yeah the air handler is more challenging to deal with because the doors need to be accessible. The drain, tubing, and wires would make it hard to do. You would need to completely redesign the air handler to do it properly. As far as the ducts go I have done exactly what I said by wrapping the duct with normal duct wrap r6 insulation then wrapped with foil bubblewrap stuff and sealed the seams with mastic. The difference in temperature compared to before was enough for me to think it could solve the sweating duct problem in most situations, though I have only tried it on metal duct. Flex duct on the other hand might be more challenging to deal with. I don't run into sweating ducts too often though and every situation is different.
@Mazinblaster Z Actually I remember watching a video about a company spray foaming ductwork. I can't see any reason why it wouldn't work as a solution to sweating ducts. Only problem is you would likely want to make sure the ductwork is completely dry before putting any foam because there is no telling what kind of growth might happen between the foam and the duct if water gets trapped in there. Also I don't really know much about sprayfoam but I wouldn't be surprised if water messes up the chemical reaction of the foam.
@Mazinblaster Z Anything (like spray foam) that is air tight would keep humid air away from the outside surface of the duct. This would prevent sweating.
I’m looking for answers for a friend’s HVAC system. The company that services his system was no help. His system is in the crawl space. The unit itself is sweating. I see one vent to the outside. The crawl space is well insulated. There’s no air circulating in the space. I’ll have him watch this video to see what answers he can find. Thank you.
Here in East Texas we have elderly leave their door open with just a storm door closed to see outside all day so it's foreign to them to keep the door closed because they grew up doing this.
In this humid situation and ERV should be used. With bath fan every 90cfm of humid shower air suck out, sucks in 90cfm of outside humid air through cracks and gaps. ERV instead is way better control.
I had to rewind a few times when “Bert” ask why” I feel your pain it’s funny I see your reaction love it when you say don’t do that Bert stop being a clown! Lmao
It's such a battle. We are spoiled these days.. hvac everywhere. So now we want it refrig cold in our living space. Especially in hot environments. I wish I could get one of the 30 hvac companies to give me an expensive option. To common they want the quick easy option. Change the unit (its already a new unit) or apply a bit of tape to some spots closest to the attic hatch. I need a redesign of the duct system. ( there is a big story to this). It's to the point that I am educating myself and will just do the work myself.
Where I live we don’t have much moisture. One thing that intrigues me is how come coolers don’t sweat ?they are well insulated and you put ice and keep your beers cool, but no seating
What about in a mobile home? We have no attic. My bathroom which is closest to our air conditioning unit, vent is sweating all the time. Any suggestions?
I’m hoping another tech can help me out or even the guys at hvac school too. Here’s my scenario: I have an ahu on the second floor in a tight closet that is not conditioned. The ductwork in that room sweats and drops down into 1st floor sheetrock. Originally the closet was not sealed off of the attic air. So since I’m in a new build house the guys came back and sheetrocked the closet closed. But the supply duct goes up hits the ceiling then goes down into floor where the ducts are ran on 2nd floor. My humidity in the house is at like 60%. Anyone have any suggestions I’d love to hear. I’m a commercial tech and we’re generally pretty good with this type of thing but came back to hvac school to re-up on some humidity and duct sweating tips. Thanks guys
I am that old guy engineer you spoke about in your video. I have a sweating coil. My house is a story and a half and my unit is in a walkin attic that is partially sealed. When the attic was almost sealed I had everything sweating and mold build up. I installed a 4” power vent that is humidity and temperature controlled to vent to the upper attic. That helped but did not solve the issue. I noticed the air was cold and stagnant around the sweating unit. I installed two very small fans. One blew air on the unit and the other blew air from the unit to the exaust fan . The two fans are controlled by a power ventilator temperature/humidity controller. The fans come on at 70% humidity. What the fans do is keep the attic air warmer so it does not condense easily on the unit and second, when it does condense it will helps dry the unit once it shuts off. I have considered your idea with the dehumidifier and if the fans do not work, I may do it. Another option is to condition the space. All I need is to seal it off and tap into the duct work. I think my energy efficient fan method will work.
What happens in the scenario where metal crawlspace ducts are sweating and the crawlspace has recently been sealed and dehumidified but the underside of the floor was not previously insulated? Does it now raise the inside temperature due to a warmer crawl space?
Alot of this doesnt apply to the area I live in. No one has a furnace or ducts in the attic. Its all in the conditioned space basement. (Northern states)
I've been in HVAC for over 30 years I watch videos like this because I'd rather watch this than tv I read the comments.And nobody has hit the real issue yet in my opinion think about a house that was built 100 years ago it's not insulated very well it's drafty but one thing it's not and that's moldy or wet underneath it because air can move through the entire house we build houses completely sealed now days then spend thousands of dollars to recreate air circulation through the house when you seal the crawl space add a dehumidifier and a supply vent that's controlled air circulation same thing in the attic
Riddle me this. Humidity outside: 30% Humidity inside upstairs apartment: 70% A/C unit struggles to maintain temperature of thermostat in the heat of the day (set to 67, it is 75, and thermostat is in a dark hallway). Vents sweat, rust, and have splattering of mold. Running 3 dehumidifiers, one designed for an entire basement, in the same space, does not improve humidity; sometimes it makes things worse while fighting with the A/C more. Changing air filter once every 3 months, even if not appearing that dirty. Tried opening the windows and doors to allow summer air outside at 27% humidity inside, with fans blowing. After 1 hour, humidity inside went from 71% to 69%. Humidity near the vents and inside the air filter is 85% or worse. The powder detergent for laundry up high in a closet in hallway clumps horribly as if it's been soaked. Apartment technicians refuse to look at it and have never come, even when they claim to have reviewed and resolved the issue. A/C unit is on the roof. No plants, no standing water inside except the cat's water bowl, vent to bathroom is closed, certainly no humidifier, no neighbors below, not next to pool.
@@vaseasun A few days after I commented, I realized this but that still does not help. Regardless, having 3 dehumidifiers and no help is beyond frustrating and should be physically impossible. All this past week in the heat of the day it's been upwards of 85% to 91% humidity inside or 63-67 dewpoint. The indoor dewpoint has never been below 59 in months. It does get better than outside in the middle of the night, but that's not saying much. There hasn't been rain in over a month. I live 290 miles away from the Gulf Coast and about the same from the swampland states. Local weather follows very close trends to Phoenix, AZ. Problem does not persist in nearby houses of friends or family; I've taken my temp/humid monitor over there and can record dramatically improved results and none of them use dehumidifiers.
There's too many variables to diagnose over the internet. Are you sure the condensate from the A/C is draining out of the apartment? Are you on a top floor with a roof above you? Running 3 dehumidifiers does create a lot of heat. Not surprised the A/C doesn't keep up. My first thought would be to check if your evaporator coil is clean.
Great information! Sweating ducts and equipment have always stumped me. I would try those usual fixes, fan speed, insulation... Great class!!
Absolutely, I've seen this in many of my rentals.
Enjoyed the video but the solutions advised of in the video fell far short what should have been the case. The real issue re the equipment in unconditioned space is that the build quality on most air handlers and ductwork are not designed for Florida and other high humidity areas. Since that is highly unlikely to change, go look at how the industrial community prevents condensation on pipes/equipment in areas where humidity cannot be controlled easily. Some solutions are a LOT less expensive than the initial and ongoning cost of a dehumidifer. That said the air obviously needs to be conditioned/dehumidified as is appropriate to prevent condensation on other components of the structure as well not just HAVC equipment! The goal of an HVAC technician SHOULD be to educate on what is needed to prevent/control unnecessary moisture damage to all structural components not just in the primary occupied space and the components that do the conditoning. Obviously some of those other solutions will require referals out. A follow up video on a complete list of realistic solutions (as opposed to ripping out insulation/heat barriers SMH) is appreciated for those that seem to struggle with recognizing solutions on their own.
My dude, I've loved all your videos till this one. Insulating ductwork definitely works just like putting my beer can in a coozie keeps the sweat ring off the table. Doesn't matter if it's internally or externally insulated it still works (I'm in Texas). In a home, sweating vents are usually because the return air to the handler has been compromised and the evaporator is sucking in wet attic air (in Texas it tends to be installed in the attic). Re sealing tends to do the trick. Keep up the great work and mostly love your videos.
@@williamkorver9856 To put a dehumidifier in the attic which supposed to be vented to cool of the shingles and keep heat gains low... what a halfwit. No wonder the students couldn't answer his questions.
Swamp cooler for states NC and below
I watch your videos NOT because I am an HVAC guy, but just a homeowner who wants a good understanding about my system and how it should be serviced and maintained.
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My air handler unit is in the garage and it was sweating like crazy all the time (FL-Southeastern) until I bought a dehumidifier and placed it in my living room. It runs about 1 hour everyday keeping my humidity below 40%. I haven't seen a drop of water again around the air handler since then. Its perfectly dry all the time. This channel is awesome. Thank you
@Wayne B Hmmm. very interesting. Thank you.
I'm about to try that right now! Luckily I have two dehumidifiers I found while scrapping for metal that I didn't scrap and I'm grateful now!
Is this method still working for you during this extremely hot and humid 2023 FL summer? It’s so humid rt now and just started leaking for the first time from my AHU, which is also in the garage. AC unit is almost 2 years young, that makes a difference.
I would have never thought to put the dehumidifier in the living room. Very curious if is this is still working for you right now. Will likely be trying either way at this point though. Thanks
Yes, it’s working really well. My humidity is around 32-34% all the time. Now, there is something else I learned, blower speed. For some reason my blower speed was really low. It’s called CFM. It was low but not to the point of freezing the evaporator but it did an excellent job dehumidifying it too. Another factor is the thermostat setting. if its too low (72 F), you can get I lot of condensation. So, it’s a lot of small details that increases this condensation in my garage AC units. Good luck, keep searching
@@MichaelHernandez-lc2wb thank you! I actually got a wet/dry vac and used vinagre to suck out a bunch of shit that collected from last year. Apparently my sis didn’t know to do this monthly…. Worked right away and dried up leak going down garage… granted here ac unit is less than 2 years old. So if anyone reading this has tried this and has cleared the line, I suggested calling a tech for sure!
I’ve chased this issue several times and now understand why it seemed to always be worse. Thank you. Great information
Learned more with this presentation than the college I went to. Thanks
Sharp instructor and well spoken.
My wire-tap phone must have been listening again and recommended this video. I am experiencing all the problems described here and my HVAC guy couldn't figure out in 4 days what you solved in minutes. He even had me put in powered attic vents which are drawing in more swampy air.
6:51 -We use this concept in refrigeration by installing mullion heaters in the door frames to increase the temperature to above the dew point of the surface of the door facing.
Been dealing with a customer for the entire year asked multiple old timers and non of them solved the issue like you did today thanks I feel like a took agigant elephant off my back
The point of increasing attic air flow and moisture as a byproduct. Good point.
Top of the line advice...don't b afraid giving the customers solutions" without thinking about their expense and decisions...lots of techs are afraid to do it...
I really enjoyed your class. A much needed class. I had my Coils Cleaned. This was necessary. My workers didn't sanitized my Coils after. This lead to a stink, causing me to replace Air FILTER/s. Then I called in a H-vac Company, and I told them as I wrote you, it's stinks and I'm using much more AIr Filter/s than needed. Now I was having my Coils Sanitized, and cleaned my motor, which was growing mold. This was just for a Vent Cleaning. Look where it ended?
Now, I feel cold from my vents. Having a Duct Tape Smell. I don't have any leaks, great, but why does my apartment smell like trash? In Summer months the A/C will never stop running with this problem now. I really need an understanding why I smell cigar smells. I never did before.
Another weird matter, FL, it's 73 degrees, my unit is on 78, why would my unit go on at this degree? I had to raise my Thermostat to 79. This is a problem. What, I don't know. Any suggestions?
Put the air handler in the home's envelope.
Equipment, Supply Duct and Return Duct should never be outside the envelope. If energy conservation were paramount, Energy Star, DOE ect would make building code require equipment to be located inside the home. No one wants to give up 12-14 sq foot of foot print.
OSHA should require this also, I've been in 130-150 degree attics, not a safe condition.
I agree 120%!! So many people want another closet to cram with junk instead of putting the A/H in there. Lasts longer, maintaining it happens more frequently, doesn't sweat, and I'm sure much more. What do you gain by putting it in the attic....a spot to store junk....thats it.
You must not live in Texas or anywhere with new home builds. All handlers are in the attic.
@@thomasnew8606 We average about 4 new homes a week, live in Kansas, 99 percent have basements. Good place for HVAC duct and a place to go during tornado season. Also adds extra living space. Attics are terrible places for HVAC., We do a couple new home attic installs a month. Have to increase size of A/C to accommodate attic heat.
@@skikansas66617 very few homes in Texas have a basement as it adds a ton of cost to a home build that’s not needed. An conditioned attic is just fine to run the hvac but few homes have that as well it seems.
@@thomasnew8606 ...Same in SC.....but the point is still valid. Place the Air handler and system in the conditioned-space. Hard to do, as SC is one of a few places where one can buy new, SMALL homes...and most of these are built on-slab. I get it, you can give up some living space but its a tough market for this design change to take root.
Insulating the ducts properly will stop them from sweating
Have been a fan of your teaching methods, there are many channels which put light on the subject, but the way you describe things, it's just so simple and easy to grasp. Keep up the good work.
If you have metal registers that are sweating try installing plastic registers and sealing around them to keep warm/humid attic air from leaking around the ceiling opening.
This video came to me at the perfect time. I’m going to a customers house to finish an air handler and condenser install, but also the vents in two of her rooms are sweaty and my boss wants me to put foam tape on the backside of the air tech registers to seal it from the attic air.
Slight counterpoint...... in the South where I live, air handlers are located in attic that ( as they normally are built today) are vented attics, yet run very hot in the summer. The air handler has the evap coil inside which produces the cold air that gets sent to the home's "conditioned -space" via the ductwork attached to the air handler.. BUT...if the air handler cabinet has poor insulation, as is often the case, the interior cold surface temps of the air handler cabinet.... migrates ( conducts), to the outer-surface of the air-handler cabinet. The outside then gets cold enough to condense the hot-humid "atmospheric" air found in the attic. In this case....it is indeed the addition of MORE insulation onto the exterior air-handler cabinet.....to minimize the cold temp migration affect from the inside, that can help. After adding a suitable amount of insulation to the outside surface of the air handler cabinet...it's exterior will be "less-cold" ( warmer) on its outside surface.....and if done enough....won't have the exterior temp be so cold as to go below the attic-air dewpoint. Here is one example where adding insulation does work.........the same argument can be applied to additional insulation wrap on the insulated ductwork that snakes around the exposed areas of such an attic. All correct.....right?
I wish that question would have been answered. I too think proper insulation around the ductwork would prevent sweating. I just had a new Trane HVAC system installed in my crawlspace replacing a 20 year old system. I had all the ductwork replaced using steel ducting for the trunk line and returns. The system was installed in April 2024. I went under the house yesterday to replace the filter. I was shocked to see water droplets all over the trunk line. The feeds to the registers were fine. I believe the contractor used too light of an insulation around the trunk line. I called them today and asked what would you have done if the trunk line ran through the attic. He said we would have used R8 wrapping. He said in a crawlspace the code doesn't call for that. I said, if I would have known that I would have paid extra for R8. Now I am concerned I will have a black mold problem if I don't remedy the sweating.
@@tiger859986 ...basic thermodynamics....and citing "Code" for not doing something that is technically sound and professional.... is a crutch. Try having him see this point or maybe then only court actions may work for unprofessional work that can cause health issues? Aside.....the factory manual for my air handler specifically identifies that additional insulation may be required to encapsulate the air-handler in the attic ( even though a thin layer of insulation is factory installed on the interior surfaces).
@@tiger859986R-8 insulated ducts in crawlspaces still have exterior surface temperatures below the dew point in a typical humid climate crawlspace. As stated, effective countermeasures include raising the temperature of the environment and/or removing humidity from the environment, neither of which is practical in a ventilated crawlspace. Adding duct insulation isn't likely to increase the surface temp of that duct enough to get it above dew point. Encapsulate the crawlspace
Hi. My air handler is in my garage and it’s sweating and black mold keeps ground around the white mastic at the top and mold is growing where the insulated pipes go through the ceiling above it. Do you think the pipe might not be insulated properly above the ceiling? Also how can I prevent the mold from growing on my air handler?
@@MosesDaverman_Realtor ...I'm not there to see the specifics but in general mold occurs in the presence of water and maybe a temp difference.....you have to open things up and remove the mold.... Borax usually works well, ( no bleach)...or Zinzzer special paint over the area afterwards? Then, yes....go after why it happened in the first place, like additional insulation with a vapor barrier.
Fantastic! I felt like I was watching Abbott & Costello announce the starting lineup beginning with "Who's on First Base?"! Condensation! Dewpoint! Humidity! Saturation! Great educational video! I just wish I could help my parent's HVAC and Home Repair Issues! We live in the original "Redneck Riviera" of Florida. I am going crazy trying to find Craftsman and Experts in any field - it seems as though most are Grifters and that the Grifters get more support from the Florida State Government instead of the Property Owners! I do not know where to begin ---> the state government and the insurance industry forced us to get a new roof! Now the state of Florida is demanding new roofs every 10-to15 years! We had 10-years of life remaining on the roof that my parents had installed in 2004!
Your classes are so easy to comprehend for us newbies to Hvac, 😊!
Professor Ward recommendation is dehumidifier in the attic with Harvard loop on the suction line and all duct work with the Adamek bend. Customer Ward wears his cap and gown on all service calls
No discussion on insulating the ductwork in the attic? Doing so would both save energy and reduce or eliminate sweating.
I was shocked what a nonsense he spitted out.
My duct insulation is absorbing the moisture and causing drywall/mold problems.
@@JaimeBlanco666 it should be vapor tight - insulation at least 2" covered with aluminum foil sealed everywhere with aluminum tape . This way no water vapor will get inside and condensate.
@@grigorshukerski4689 and what about when your AHU itself is sweating? This video didn’t spout nonsense. I just think you don’t quite understand dehumidification.
@@grigorshukerski4689I heard a lot of things didn't hear any nonsense though can you elaborate?
It's been 2 years since this video has been posted and I am 95% positive that Bert has kicked this guys ass by now.
I really enjoy your videos.
Thank you for what you do for the HVAC community.
Great. My agency has been involved with the Weatherization program for half a century. We've gone from plastic over windows to geothermal and solar. Some of the biggest issues we have dealt with (I'm from Oklahoma and only Fla and OK know what real humidity is....Ha) is sweating vents. These are full new HVAC install to upgrades, insulation, attic sealing and air flow and on and on.
I'm now 68 and retiring. I've seen it all from retrofit (toss storm windows and blow insulation) to dealing the Lead based paint. I've always felt bad for my crews. Anyway, I have a nice house built in the 70's. Cathedral ceilings and High efficiency (seer) HAVAC. This is the first year one of my vents in the ceiling of living room has started to drip. It's has the cathedral ceiling where this drip from the vent is. It gathers on the outside of the vent till it hs enough moisture to drop a drip. Temps were at or over 100 with Humidity of about 40%. My vents are all wrapped and sealed with insulation and R21 blown. We had a ridge vents installed with the last new roof for better High Low venting.
What can I do to stop this one vent from dripping. Help
The attic dew point does not change when you change the temperature. Condensation forms when the duct surface temperature is colder than dewpoint. However, warmer attics will warm up the an uninsulated duct surface a bit so I could see how it reduces condensation.
This was a super helpful video for me. I Installed an exhaust vent from our OTR microwave in our kitchen up through the ceiling, attic, and capped it off on the roof. Very short run (less than 4 feet) since it's 1-story home and the range is close to an exterior wall (6" round straight duct). Temperatures today were 102 F with a dewpoint of 79 F (51% humidity).
I ran the hood vent (new fancy schmancy OTR microwave, strong exhaust fan) after heating up some food and went about my business. Left the fan on for less than 10 minutes. I go back in the kitchen an hour or so later and hear water dripping and see water slowly dripping from the side of the OTR microwave where it meets the cabinets. I look up above the OTR microwave at the duct that is inside the house and see it sweating quite a bit.
So I'm all worried about if this is a new issue or one that's been happening for awhile and start researching. I figure I need to insulate the duct before I better seal the gap between the duct and the ceiling (which definitely allows warm attic air in).
Well your video perfectly explained the issue for me and has saved me from making the mistake of reaching for insulation instead of just focusing on sealing. And you've also calmed my worries about the portion of the duct in the attic since, as you said, air moving through the duct does very little to the duct's external surface temperature.
Only annoying part for me is that the duct goes from the OTR microwave through the tiny cabinet above the microwave, and then through a like 4" tall space between the top of the cabinet and the actual ceiling, and then finally into the attic. I can easily seal up the gap between the inside of the cabinet and the space between the top of the cabinet and the ceiling. But there's no easy way for me to seal the gap between the actual ceiling and the attic (but luckily that hole/gap is muchhhh tighter, albeit not tight enough given the warm air that can be felt rushing in to replace the air exhausted out). I'll probably just have to seal it up from within the attic even though it's too cramped to even crouch at the point where the duct is 😅.
I'm a HVAC tech like most of us here. I personally had sweating vents in my 2nd floor system ( hvac in attic) . I found the original hvac contractor had not sealed the boots off the ducts right around the sheetrock and the boots were poorly insulated. Some had no insulation on the boot. The moist hot attic air was coming around the boot , gaps ( 1" or more ) mixing right at the diffuser face. So very cold and very moist hot air cause vents to condense on the face. Everyone of them were like this. I end up pulling every boot and redoing some of the runs completely. Everything was sealed tight from the condition space and boots were properly insulated . No more sweating vents....
I think this sounds like it very well might be my issue. I have only one vent that has a sweating problem (and it happens to be right above the air handler so I was the dummy thinking the air was colder and that was why). I have no attic access and the vent is 15ft or so up so not the easiest to get at. Any suggestions for a quick fix?
@@ByteHeisenNerd you can pull the diffuser off ( supply vent ) some installers would nail the boot from inside on a roof rafters or a nailer cause they don't have a lot of room above to work since there is no attic. If you find that they are nailed on inside you can pull the nails to free the boot. Then you can maneuver it around in the ceiling to put small pieces of insulation. This will be a royal PITA cause it won't allow for a lot of room. Reinstall the boot by nailing back tight. Use caulk to boot tight to the sheet rack and reinstall diffuser.
@@ByteHeisenNerd if there is no way to remove boot from below then you will need to square up a section of sheet rock you want to remove. If it I was doing i would cut a 2'x rafters bay width ( 2'x16" or 2'x24" ) piece of rock out. This would allow you more then enough room to put nailer ( scab pieces of wood ) back in for your sheet rock seems and room to insulated the boot.
@@pineychristian thanks so much for the reply! I appreciate all the detailed explanation. I will make my way up and try option 1 first, then cut back the rock if it’s not possible. Thanks again!
My air handler inside home. I insulated drain pan with armaflex, 1/4" steel drip pan under that, cork under drip pan. Walls pour foamed that air handler is in. Coil room insulated on inside with armaflex. All duct solid steel, air sealed 100%. All ducts insulated with bioceramic r7 (hy tech) paint then insulated with reflectix, no gaps anywhere. Positive pressure condensation drain with skupper valve. 4" fresh air intake triple filtered, shut down in extreme temps. Ecm main fan and ecm fresh air fan. 6 uv lights surrounding coil set to timer. Crawlspace partially conditioned with temp and humidistat. If you have more than 10% diff you will reach dewpoint from what i understand. House is confortable. All walls, subfloors painted with insulating ceramic paint (hy tech) with concrobium and zinser paint. You are right you need to lower humidity in home to prevent condensation or keep the variation of temps below dewpoint. Btw bath walls do not sweat ever, only windows. Bath fans set with auto humidistats. All wall and ceiling and floor protrusions sealed 100%
I had my attic spray foamed and they would not do so without removing the insulation. They said it would allow condensation on the ceiling drywall and grow mold/ mildew.
The attic is way cooler, considered conditioned space. Luckily our humidity near Dallas Texas, we haven't had any condensating ducts or vents.
You just took me to school on moisture. Thanks
I think the issue is that most people care more about lower power bills than some black mold on the outside of ducts in an unconditioned attic. A conditioned attic space, so all the ducts run in the conditioned space, is the best solution... for new construction. I hope all local codes are moving to enforce this. Put everything inside the conditioned envelope.
Geographical issue. In southern Commifornia moisture is a blessing. Send your humidity over here.
Really great teaching session. Bryan knows his stuff. It is scary and unfortunate that the students in this class are not committed to understanding the profession they are trying to work in. After this the client calls them for service, it looks good but lots of problems because these tech's don't know what they are doing well enough to provide successful outcome but all good and well enough to be certified. As an industry professional I find this most unfortunate.
Nothing was mentioned about simply insulating the ducts. Please tell me if I am wrong but insulating the ducts will mitigate the dew point issue no?
Thanks for the video. I'm having sweating problems with a portion of ductwork in the basement that has been finished/boxed over with drywall. Small amounts of water are coming through a ceiling vent and portion of the wall in the finished bathroom in the basement. Also, I have paneling on a wall (on the other side of the basement bath) that is below the return and on the outside wall that is warping from the sweating ductwork. So, what's the issue? I'm already running a room dehumidifier in the basement. With that, the relative humidity stays in the 50/55% range. Should I check for an infiltration problem on the outside wall of the house? Should I raise the temp that we run the AC at (currently 74 degrees for the house with the basement temps around 70 degrees)? Before I start tearing down walls and the ductwork boxes it would be good to have some idea what the cause of the problem might be.
Thanks to anyone who might have some insights.
In the end, if I can't figure it out, I'll try to get an HVAC guy in who hopefully knows what they're talking about.
As always , great teaching Bryan!
I dont think the solutions in this video could be the best. Obviously if you dehumidify the space around the ductwork you are not going to have trouble with ducts sweeting, but I think is not practical. I think the best solutions is a good insulation in the ductwork, if you insulated the ductwork, the external temperature of the duct is going to be above the dew point and the ducts are not going to sweet. Same thing with the air handler unit. The best way to avoid this problem is selecting the right equipment in the beginning of the project. This could be a solution if it is too late and anything else solves the problem.
It is being implemented in encapsulated attics. A dehumidifier is installed
hi, very informative. thank you. what humidifier for attic you recommend ? I have a 20 year old house that has pink fiberglass on the floor of my attic. my house is 3500 sf and my attic is very humid as I live in south florida
Some interesting info. One point of correction is moisture moves by vapor pressure not air pressure (airflow). air curtains don't keep moisture out. Doors only help if they are sealed. Kitchen pressurization only reduced infiltratration or fresh air. You still need vapor barriers to keep moisture from migrating in and out of buildings
It doesn't make any sense to increase heat gains just because the ducts are sweating. It is like killing a fly with a cannon.
People are talking about zero loses/gains houses nowadays.
Just insulate your ducts well enough,so the surface will be above dew point and seal with vapor barrier ( the ducts, not the attic).
Condensation on the vents can be solved by mixing the air leaving the evaporator with additional amount of air from the house in a such a way so the air exiting the vents is above dew point ( more air flow with temperature just above the dew point).
Not sure why adequate insulation with an appropriate vapor barrier would not keep moist air from condensation on the ductwork. This is the approach in most mechanical rooms.
Thank you I was about to do the wrong thing, I need to seal !!! And use a dehumidifier
If you have a supply grill in a vaulted ceiling and its sealed and insulated perfectly but sweating put a curved blade register and it will cool the area near the sweating register done it many time after other company tried everything works every time. If you have sweating spiral duct in a restaurant and its dripping on the customers all you have to do is direct the air up instead of vertical or down then the area around the sweating duct work will be cooled down and no more sweating. If you have sweating equipment in an attic unvent the attic and seal the attic then put a small portable dehumidifier in the attic problem solved.
I live on the Gulf coast. Fifty years ago we didn't ventilate our attics and they would get to 140° or higher in the middle of summer. It would take all night for that temperature to come down to dew point. By that time, the sun had come back up and reheated the attic and we had zero sweating problems.
Fast forward to today and with ridge vents, soffit vents, whirly birds, powered fans, white metal roofs etc, attics don't get anywhere near that temp. If it's 100% humidity outside and your attic is ventilated, it's also 100% humidity in your attic. Add more efficient equipment and variable fan speeds and the air temps in ducts make it almost impossible to stop the sweating especially on older systems that still have R4 wrap.
People hate to hear it but I tell everyone to stop up all the ventilation, dehumidify the attic for a few days and put R30 on the ceiling. Shingled roofs don't last as long when it's that hot in the attic but at least it isn't raining on your ceilings. Been doing that with some success for fifteen years or so. I wish I would have seen this video decades ago, was a lot of trial and error figuring this out. 😂
Gulf Coast Wisdom. Similar in GA, but less stringent. Humidity can manage itself if you do not over-design a system or over-ventilate; that hot attic is your friend here in GA, too, to a point (110F is fine).
I needed this info and am most appreciative! What a blessing!
What about closed cell spray foaming the ducts? Sealed and insulated from attic air right?
In SWFL, was told we needed a new 4 ton. Purchased 4 ton from them, they installed it in attic, less than a year later and its dripping into our ceiling and find out they installed a 5 ton air handler, but kept fan speed at stock (guess it can be reduced to medium to act like a 4 ton?). Anyway, terrible sweating on unit that is causing water damage to closet/ceiling below it. They are blaming our older ductwork that they said is too small/old, but didnt say it was an issue before and obviously they installed things incorrectly from the start. Very frustrating so far.
As a new guy, these seminars are great.
Ohio We Get Dewpoints over 70 fairly often Duct work in Basement was getting Damp. Put in a 6" Round to the Return Air and Angled it such that the Air flow in the return helped induce some air flow @ the Furnace Blower. The other end is vented outside. Thru an ole Coal Scuttle (They Make Special Vents for this) The Scuttle just conceals that it even exist. My Unit is Slightly undersized from before the addition's 4T (Load Calc says I need ) 4.5-5T so it tends to have long run times. Before I needed to set the Thermostat at 70-72 to be Comfortable Now I have to wear my Fuzzy Robe at 75-76 because it dries out the air so well. I do on Occasion hit the times when it is "Muggy" outside and Coolish (Mid 70's) that I need to bump the Temperature down a bit. Duct Work stays dry. Slight Positive pressure on the house when the AC (Fan) is running Reduces Humidity infiltration. That is I believe why it is cold at 75 when it is hot/humid outside and I need to turn down to 72 when it is cooler and Muggy outside.
I’m gonna have to watch this a few times to get this info to sink in. Holy smokes great video.
High humidity air hits the surface with temperature below the dew point will result in water. To stop the water, you need either high temperature or low humidity. High temperature means more energy cost in winter. So I would think a good seal + dehumidifier would be the solution.
when you mention sealing the attic, can it just be the ductwork sealed off with duct seal? or does it have to be all ventilated areas in the attic?
So is caulking around the ceiling air vent a good idea if the vents are discolored? i.e.remove the air cover and calk between the ceiling drywall and the air duct?
I had this problem in my first place over 15 years ago. Instead of all those expensive and complicated solutions I just replaced all vents with plastic vests. Problem solved. Not sure last time I looked for them it was harder to find.
I live in NJ and on very hot humid days above 90 2 of my 6 ceiling vents sweat. Sometimes sweat enough to drip on floor. It has damaged the drywall on ceiling around the vent. The unit is 20 years old seems to run ok and comes on and off throught out the day to keep 76-78. I have no attic space I live on top floor in a condo with vaulted ceilings. What can I have done that wont have me throwing money away when I call a hvac company. My unit has never been serviced since ive moved here 16 years ago. I change filters 1 time a month and always have
condensation from my vent on vaulted ceiling!! In Florida
This is gold!
Why do we insulate refrigeration lines and chilled water lines if insulation makes things worse?
Air duct that runs from basement up to first and second floor all behind a laundry shoot. Only accessible from basement level. Lots of sweating and moisture collecting at bottom of the basement floor in laundry shoot. It seems to only be insulated for about the height up to the first floor. The insulation is completely saturated and dripping. We just redid our kitchen on first floor and opened up the wall for some plumbing changes and it also allowed access to that ductwork. And our contractor just wrapped about 8 more feet of ducting with regular wall insulation batts and now the wall is sealed up. What do i need to do? Trying to learn anything i can before hvac tech comes out so i have some idea what to expect
Usually after days of rain we get these calls, condensate pumps run more, moisture appears on ducts and supplies and the accusations the system is not working. I always ask what modifications were made to construction before this issue..some have an answer, some don't but regardless, the problem exists now and hopefully options are on the table. Sometimes the owner will have blueprints of the new work that could help find where the moisture ladened air is infiltrating the conditioned spaces. .what a job we techs and contractors have .
Good job 👍😎 I have a problem on a closet I’m going to tomorrow. Duck is sweating. Only in that room. I think the air is too slow to that closet in that closet gets very hot for some reason. It has an adjacent attic on one side and it also has an attic above and behind it has a call wall on a condition space 72°. This area had just recently been done a couple years ago when they found mold in there on the walls and near the ceiling. That wasn’t just the other area there were some other spots as well. The house has three infinity systems. Currently there is only one duct sweating. More will be revealed tomorrow when I check on it again. Attic is very hot and 71° upstairs as well. I told him to try 73°
Increase the superheat on your air con. Dehumify and reduces cooling capacity. Stops the issue of cold and humid room. I used to use 2.4kw heater in humid summer untill i discovered 10 deg superheat on cool mode fixes this. Stops mouldy ceiling vents too
Two new vertical air handlers were installed in ground floor commercial bldg unit. Air handlers are in closet, next to a room in conditioned space. The door between room and closet is not sealed, and it has a vents built into the door. Vent "fins" are stationary and angled down on the adjacent room side. The installers cut into the cold air sheet duct above each Air Handler and added louvered vents. Now the closet with the air handlers is a conditioned space and ducts are sweating and dripping. Seems to me this is not a correct installation. Climate Zone 6B
What about doing double wall ducts so the outside temperature is closer to the ambient temperature and the inside can fluctuate? Just like the windows?
Would certainly be better than uninsulated ducts.
I had the same problem with 2 rooms in my house and they HVAC people who installed it could not figure out why. They put in another return (I think). Initially no sweating but returned. If U remember right what solved the problem was dehumidifying to 40%. Which this video was available when I was looking for a solution 2 years ago.
I have a question, wouldn't insulating/sealing the ducts better and insulating the outside of the air handler also solve the problem because by doing so you are increasing the temperature of the surfaces of the ducts/airhandler. In theory you could just increase the amount of insulating material until the surface temperature is close to that of the attic?
Too right my man, and its less work then ripping off the roof installation 🤣
Yes in theory but in practice no. You would also have have a vapor barrier around the air handler
@@madzmadeit yeah the air handler is more challenging to deal with because the doors need to be accessible. The drain, tubing, and wires would make it hard to do. You would need to completely redesign the air handler to do it properly. As far as the ducts go I have done exactly what I said by wrapping the duct with normal duct wrap r6 insulation then wrapped with foil bubblewrap stuff and sealed the seams with mastic. The difference in temperature compared to before was enough for me to think it could solve the sweating duct problem in most situations, though I have only tried it on metal duct. Flex duct on the other hand might be more challenging to deal with. I don't run into sweating ducts too often though and every situation is different.
@Mazinblaster Z Actually I remember watching a video about a company spray foaming ductwork. I can't see any reason why it wouldn't work as a solution to sweating ducts. Only problem is you would likely want to make sure the ductwork is completely dry before putting any foam because there is no telling what kind of growth might happen between the foam and the duct if water gets trapped in there. Also I don't really know much about sprayfoam but I wouldn't be surprised if water messes up the chemical reaction of the foam.
@Mazinblaster Z Anything (like spray foam) that is air tight would keep humid air away from the outside surface of the duct. This would prevent sweating.
So, heat not cool for moisture to keep the exchange from sweating. Did I hear that right? Even in the summer!
Great presentation!
Yeah I've been seeing a lot of reasons to insulate and condition the attic lately. Seems to be the way to go.
So no dehumidifier? Or just seal attic and less insulation?
I’m looking for answers for a friend’s HVAC system. The company that services his system was no help. His system is in the crawl space. The unit itself is sweating. I see one vent to the outside. The crawl space is well insulated. There’s no air circulating in the space. I’ll have him watch this video to see what answers he can find. Thank you.
Very good class
i love your video guys, your random jokes makes iteven more enjoyable to watch
When he said "think sealing" what does he mean exactly? Seal around the vent from the outside or from the outside? I'm confused
Legendary, Rick Sims I miss that gentleman started my journey
Here in East Texas we have elderly leave their door open with just a storm door closed to see outside all day so it's foreign to them to keep the door closed because they grew up doing this.
Great explanation. Can you please do a video on how to set an hrv in conjunction with the hvac system throughout the seasons of a year.
In this humid situation and ERV should be used. With bath fan every 90cfm of humid shower air suck out, sucks in 90cfm of outside humid air through cracks and gaps.
ERV instead is way better control.
I had to rewind a few times when “Bert” ask why” I feel your pain it’s funny I see your reaction love it when you say don’t do that Bert stop being a clown! Lmao
been in giant attics with a dehumidifier....size of attic? Great topic!
It's such a battle.
We are spoiled these days.. hvac everywhere. So now we want it refrig cold in our living space. Especially in hot environments.
I wish I could get one of the 30 hvac companies to give me an expensive option. To common they want the quick easy option. Change the unit (its already a new unit) or apply a bit of tape to some spots closest to the attic hatch.
I need a redesign of the duct system.
( there is a big story to this).
It's to the point that I am educating myself and will just do the work myself.
Great video very informative.
What profession should I be looking for to solve this problem?
The moisture through the vents caused mold on my wall.
Where I live we don’t have much moisture. One thing that intrigues me is how come coolers don’t sweat ?they are well insulated and you put ice and keep your beers cool, but no seating
Great information.
Could you vent some of the moisture back to the condition space to help with moisture in the condition space 🤷🏼
5:52 - A glass of cold water as a dehumidifier - what a concept!
That was well taught.
Make your ac unit 1/2 ton small so it runs a little longer and will dehumidify it better
What about air handlers in basements? Same concepts?
What I can I do about sweaty duct work in my crawl space, I live in Tennessee fairly new home.
What about in a mobile home? We have no attic. My bathroom which is closest to our air conditioning unit, vent is sweating all the time. Any suggestions?
I’m hoping another tech can help me out or even the guys at hvac school too.
Here’s my scenario:
I have an ahu on the second floor in a tight closet that is not conditioned.
The ductwork in that room sweats and drops down into 1st floor sheetrock.
Originally the closet was not sealed off of the attic air. So since I’m in a new build house the guys came back and sheetrocked the closet closed. But the supply duct goes up hits the ceiling then goes down into floor where the ducts are ran on 2nd floor. My humidity in the house is at like 60%. Anyone have any suggestions I’d love to hear. I’m a commercial tech and we’re generally pretty good with this type of thing but came back to hvac school to re-up on some humidity and duct sweating tips. Thanks guys
I am that old guy engineer you spoke about in your video. I have a sweating coil. My house is a story and a half and my unit is in a walkin attic that is partially sealed. When the attic was almost sealed I had everything sweating and mold build up. I installed a 4” power vent that is humidity and temperature controlled to vent to the upper attic. That helped but did not solve the issue. I noticed the air was cold and stagnant around the sweating unit. I installed two very small fans. One blew air on the unit and the other blew air from the unit to the exaust fan . The two fans are controlled by a power ventilator temperature/humidity controller. The fans come on at 70% humidity. What the fans do is keep the attic air warmer so it does not condense easily on the unit and second, when it does condense it will helps dry the unit once it shuts off.
I have considered your idea with the dehumidifier and if the fans do not work, I may do it. Another option is to condition the space. All I need is to seal it off and tap into the duct work. I think my energy efficient fan method will work.
is your AC sized to accommodate an attic space? That's an enormous load to add, and your attic register/vent will be prone to sweat up there.
Great information as usual 👍 thanks for sharing.
What happens in the scenario where metal crawlspace ducts are sweating and the crawlspace has recently been sealed and dehumidified but the underside of the floor was not previously insulated? Does it now raise the inside temperature due to a warmer crawl space?
Great information
so what are you saying as your solutioin to the sweating boots? raise the temp around the boots?
Alot of this doesnt apply to the area I live in. No one has a furnace or ducts in the attic. Its all in the conditioned space basement. (Northern states)
Well,.....after I moved south...the opposite is true here...so it applies to many.
I've been in HVAC for over 30 years I watch videos like this because I'd rather watch this than tv I read the comments.And nobody has hit the real issue yet in my opinion think about a house that was built 100 years ago it's not insulated very well it's drafty but one thing it's not and that's moldy or wet underneath it because air can move through the entire house we build houses completely sealed now days then spend thousands of dollars to recreate air circulation through the house when you seal the crawl space add a dehumidifier and a supply vent that's controlled air circulation same thing in the attic
Riddle me this.
Humidity outside: 30%
Humidity inside upstairs apartment: 70%
A/C unit struggles to maintain temperature of thermostat in the heat of the day (set to 67, it is 75, and thermostat is in a dark hallway). Vents sweat, rust, and have splattering of mold.
Running 3 dehumidifiers, one designed for an entire basement, in the same space, does not improve humidity; sometimes it makes things worse while fighting with the A/C more. Changing air filter once every 3 months, even if not appearing that dirty.
Tried opening the windows and doors to allow summer air outside at 27% humidity inside, with fans blowing. After 1 hour, humidity inside went from 71% to 69%.
Humidity near the vents and inside the air filter is 85% or worse. The powder detergent for laundry up high in a closet in hallway clumps horribly as if it's been soaked.
Apartment technicians refuse to look at it and have never come, even when they claim to have reviewed and resolved the issue. A/C unit is on the roof.
No plants, no standing water inside except the cat's water bowl, vent to bathroom is closed, certainly no humidifier, no neighbors below, not next to pool.
First, you're confusing moisture content of the air with relative humidity.
@@vaseasun A few days after I commented, I realized this but that still does not help. Regardless, having 3 dehumidifiers and no help is beyond frustrating and should be physically impossible.
All this past week in the heat of the day it's been upwards of 85% to 91% humidity inside or 63-67 dewpoint. The indoor dewpoint has never been below 59 in months. It does get better than outside in the middle of the night, but that's not saying much.
There hasn't been rain in over a month. I live 290 miles away from the Gulf Coast and about the same from the swampland states. Local weather follows very close trends to Phoenix, AZ.
Problem does not persist in nearby houses of friends or family; I've taken my temp/humid monitor over there and can record dramatically improved results and none of them use dehumidifiers.
There's too many variables to diagnose over the internet. Are you sure the condensate from the A/C is draining out of the apartment? Are you on a top floor with a roof above you? Running 3 dehumidifiers does create a lot of heat. Not surprised the A/C doesn't keep up. My first thought would be to check if your evaporator coil is clean.