Yes -- best practices -- the thing codes don't always point to. So many builders are merely installers, and they either do not think or do not care. The irony is that there's a millions ways to balloon a house's cost, and they can often save money in ways that don't matter. A bath fan is noticed EVERY DAY. Kudos for somehow being able to get into a computer's new construction to point this out.
I often remind folks that the building code is the MINIMUM LEGAL standard for construction - and doesn't typically incorporate the latest best practices. Not to mention, most building inspectors are experts on the CODE, not best practices, and they often have so many inspections to do, they cannot possibly catch everything.
This video was extremely helpful! Thank you so much. Our house here in Texas was built in 1994. There is no exhaust fan at all in our primary bath. There is a window in the toilet area so maybe that's why? Maybe no code for it in our area back then? Not sure, but we are remodeling our home and considering putting in an exhaust fan. This video has been very helpful to make sure our contractor veers towards best practices. Thanks!
Lazy contractors here in the northeast can follow ‘code’ and neglect an exhaust fan as long as there is a window in the bathroom. Yup, ice cold air is so nice when you’re getting out of the shower plus, of course, it does wonders for privacy. And windows don’t necessarily vent well. No wonder folks despise contractors.
Excellent video. I am replacing my original builder provided low CFM and high noise fan. Now I see how cheap it is and the exhaust is vented on flexible aluminum hose.
You are absolutely right that long narrow flex duct has the most resistance of air flow and by the time air flow reaches to the outside there’s probably nothing left to exhaust. It’s useless to even installed it.
Well what happens is the turbulence in the exhaust causes the moisture to have allot more time to condensate. Flex duct is supposed to be stretched with 2 people holding it tight for a few minutes.
Heres the most important to note, when you lay any vent pipe flat across attic your moisture( water) is collected in the pipe and thats where 60 percent stays. 40 percent is infused into nearby insulation and some in attic air. Hence the water stain that will be on your ceiling below and eventually bubble warping out as moisture continues. Eventually that part of ceiling will fail becoming mushy swelling. TRUST ME, we did the long flex pipe laid horizontal across attic prob 20FT + WELL, that was probably about 5 yrs ago now ive had a stain my kitchen ceiling for about 2yrs +. I thought it was a roof leak. Well turns out that flex pipe laid horizontal across attic.....here goes had about 1/3 full mop bucket of just water in its bows and lags of vent pipe. In which the moisture that did reach the end of pipe was soaking insulation and ceiling. Though it was a small area 6" pipe it has spread to 12" area on ceiling before i went in attic and found the issue. With someone on ladder holding bucket below attic entry we carefully dumped a huge ton of water out into a huge mop bucket. It filled it 1/3 the way. Of course being careful when raising flex house to dump , as not to let water flow back to vent fan in ceiling. Could you imagine ......ih never again! vent straight up through roof with no lag back down. Now that i just found tjis 1 day ago weve got our work to do roof vent do it right DIY. RESEARCH HOW ITS DONE CORRECTLY
We are planning to have a metal roof installed. The roofer recommended we remove and relocate our roof penetrations. This includes a 4” plumbing vent stack and our bathroom exhaust. Our home has a conditioned attic. I have a Broan Nutone 110CFM exhaust. I would like to vent out the gable end. That distance is about 25’. If used a rigid 3” vet would I be successful in eliminating the humidity? If necessary could I add an inline pressure sensitive fan along the run to help move air more efficiently. Thoughts?
Depends on whether the Broan 110cfm is pressure compensating. If it isn’t, you can always run rigid 6” duct to a 6” sidewall vent which would minimize pressure drop across the 25’ run. Or, you could replace the existing fan with a pressure compensating model and duct with 4” rigid. Do you have a humidity issue now?
So I have an older home with 2 bathrooms right next to each other but I have no fan in neither bathroom, I want to install a fan in both bathrooms but I’m also installing solar panels on the same side and my question is can I install the roof vent next to each other’s side by side or above each other?🙏
Our builder refused to use anything other than flat paint in our bathrooms which was wild to me. Flat paint ceilings and walls and a 50 cfm fan in the 100 sq ft bathroom. The day we moved in we painted all the bathrooms walls and ceilings with satin so at least that's better. It's a huge pain to replace an exhaust fan and I really don't want to walk around on ceiling joists to do so but I do need to go up there and see what pipe they used. I would bet it's the cheapest they could get -_- Once I get caught up on other projects I might go ahead and switch it all out to OUR higher standard.
Thats a tough situation. Any paint with Sheen requires a higher level of drywall finish and is much more difficult to touch up. If they had only used a good bath fan with optimal ductwork, flat paint would have been fine.
Im remodeling my bathroom right now. Homedepot sells a exhaust kit but its a flexible cheap duct. I ended up installing hvac metal jacketing and some hvac 90s came out real good. But just to do about 5 ft of the good stuff was about $100.
Best practices - 1) A bath fan that is rated for an adequate airflow for the space, 2) bath fan that uses a minimum 4" diameter duct, 3) A bath fan that compensates for pressure loss in the ductwork, 4) use rigid duct, 5) minimize the duct length, 6) vent to the outside
@@AddisonHomes "A bath fan that is rated for an adequate airflow for the space" How would we know what is best rated for that space? Is there a guide on this? What is recommended?
@@AnthonyPerez The 2021 international residential building code requires that bathrooms have a minimum continuous ventilation rate of 20 cfm or an intermittent rate of 50 cfm. HVI, the Home Ventilating Institute, recommends a ventilation rate of 8 air changes per hour which typically equates to 1 cfm per square foot of bathroom area. They further suggest the following guidelines: Bathroom less than 50 sq ft: 50 cfm fan Bathroom between 50 - 100 sq ft: use the rule of 1 cfm per 1 sq ft of bathroom area. Bathroom over 100 sq ft: Add the cfm requirement for each fixture - toilet (50cfm), separate shower (50 cfm) separate tub (50 cfm), jetted tub (100 cfm) www.hvi.org/resources/publications/bathroom-exhaust-fans/#:~:text=Ventilation%20rates%20based%20upon%20eight,minimum%20for%20bathrooms%2050%20sq. We opt for a minimum of 80 cfm in a typically sized bathroom and a minimum of 110 cfm in an owners bath or "larger" bathroom. We use exhaust fans that are selectable between 50-80-110 cfm and duct with a 4" duct for smaller bathrooms and models that are selectable between 110-130-150 and duct with a 6" duct for larger bathrooms. We run our exhaust ducts using hard metal duct to the termination if possible, allowing for a short section of flex duct at the end if needed to make the termination cap connection.
Hi i’m thinking of buying Panasonic Whisper exhaust fan it’s 100-110 cfm. What type of duct should i use? it goes right outside my house from the attic to the roof. how many inches should the duct be?
@ 1) make sure it’s air tight where it passes through the attic 2) ensure it has a damper at the roof termination, 3) adamper at the hood is helpful too. If this doesn’t solve the issue, insulate the pipe in the attic.
@@Rayan-rw3gt rigid is best for as much of the run as possible. You can transition to flex at the vent cap. Shouldn’t have to insulate it but if it’s running through the exposed attic like your range hood, that would be a good idea.
We will consider any project that aligns with our goals of achieving a higher-performance building that provides improved air quality, energy efficiency, and durability!
The pipe and size is just fine for exhaust. Those restroom exhaust fans don’t move enough cfm’s to be restricted. Only issue on that setup is the length of it
These are the problems - the exhaust fans used are not designed to move adequate cfms with any length of duct. Best practice is to use bath fans designed to adequate airflow even at elevated static pressure from longer duct runs such as those made by Panasonic and Greenheck.
So true! I've seen it so many times and typically discover it when testing the exhaust fan airflow! So many don't understand why its important to test airflow. Its the only way to know if you have a problem before mold begins to grow on the walls!
@@AddisonHomesin the codes there should be a minimum duct run distance of 17 feet and fans that use more than 50 cfm for larger spaces. Current codes are a bit bad for building great homes with proper ventilation.
So I have been working with a local HVAC company on venting my two bathrooms in a home we recently bought built in 1980. one of the bathrooms had an existing fan but it was just exhausting into the attic. The other smaller bathroom maybe 40sq feet its the shower surround and toilet, the sink is in the vanity area outside of it, had no fan and only a small window. So I had them replace the ceiling light fixture with a Broan HD80L and they were going to run both of those vents to soffit. Well I noticed they hadnt actually run them to any kind of vent on the soffit and when I asked they were like 'oh we just hang them up near the soffit' and didnt seem to understand that with the lack of a sealed vent to the exterior more than 3ft from any other intake point on the house that this wasnt code... So they came back today and I had them run them to gable end which they completely butchered as well... they didnt install the vent screen/baffle kit correctly and installed them to close so one over lapped, then I look in the attic and they are using the cheap vinyl dryer vent type hose and instead of cutting some out because the pieces were too long they coiled it up and connected it... like this lil 80cfm fan is gunna be able to push air past that. The other one the ran it up and over a collar tie creating a big sag but also a 90 degree turn in the hose. I spoke to the owner and he said he is going to make it right and come back and fix it. Where the fans sit lower than the gable roof vent, where we have them run to hard piping will be very difficult. But living in SC should I tell them to use insulated hose? our winters are pretty mild and I doubt the attic sees more than 3 or 4 days a year of sub freezing temps. We do get plenty of hot days tho...
Insulated wouldn't be a bad idea if they are exposed above the insulation in the attic. Even though we don't get sub-freezing temps, a vented attic is typically cool enough to result in condensation on the inside of the bath ventilation duct. Anytime in the "cold" winter, that warm, humid air on the inside of the duct venting from the bathroom after a shower is going to condense on the interior of the duct. If the duct runs up hill from the fan, you have the possibility of the condensate (water) running back and dripping into the bathroom through the fan.
I share your pain with trying to get them to install these the "right" way! It would be interesting to see what the actual flow rate is through the duct as they have it connected now!!! Keep fighting the good fight!
It's to the point that 99 percent of Home repair, electricians, construction, doctors,lawyers, mechanics etc! They fail to do it right, Really! You have to research yourself how exactly all work is done the right way or get a half ass job done for you, that is a disaster waiting to happen or a complete and obvious fail on your dime and damages. Workers don't seem to care to learn correct way to do anything. It's a get er done mentality and as long as I get my money and the face presentation of job looks good, these people don't know anything about this kind of work so sorry for their luck! That's the mentality. Good enough to get paid and whoa to the clients
@@hcompton8861 I walked my wife through how it needed to be done and had her go up and knock it out. I am 6'1 350 and getting around in the attack is tight so the back end of the attic past all the pre made trusses is pretty inaccessible to me. But she ran with it and it looks 10x better than the 'professionals' I had a back and forth with the owner of the company and he ended up waiving about 40% of the bill, because they did provide some materials and did get the new condensate drain hooked up. But yeh... never trust ppl and always double check their work
Interesting. Contractors are just always trying to save a nickel here and a nickel there. How much cost would a better fan add to each unit? A couple of hundred dollars?
I was watching your show about bathroom fans. I would like to know what size of bathroom fan, I should be using for a replacement. I want to replace the bathroom fan because it creates a lot of moles and causes the dry wall and stub to deteriorate. I hope you were able to help me solved these problems
I prefer using bath fans that will move no less than 80cfm once installed. This generally means installing an exhaust fan rated at a higher airflow (say 110 cfm) and that compensates for pressure drop in the exhaust duct. Panasonic, Broan, Greenheck, and others make exhaust fans that meet these requirements.
If they are available sure but why would you want to take a 4" down to a 3" hose? Also, if you're asking is it OK as in will the fan function correctly I would say no. It's 4" for a reason. That's my opinion.
You can, but the static pressure resistance from the 3" duct will likely keep the fan from performing as designed. Going bigger is not an issue, but ducting smaller than the outlet on the fan is generally a likely failure.
I need help. My bathroom extractor vent starts to drip brown liquid every few months. My house is new. Bought new in 2022. I have to take it apart and clean it twice a year. What can I do to prebet this from happening? Under the cover there are small dials for time and H% which I assume is humidity. Can adjusting these dials help at all?
I am not sure about those dial options BUT we are told to clean our exhaust fans and should be doing so. Now, why yours would drip does seem like a problem and that would worry me at least a little.
Another factor not mentioned is make-up air into the bathroom. There should be a minimum 1/2" gap at the bottom of the bathroom door to allow air from the home to ingress and replace the air being exhausted by the fan. Failure to do so will result in a lower pressure in the bathroom that will reduce the fan's effectiveness no matter how large the vent pipe may be.
@@mrmrlee bathroom makeup air is rarely an issue, even in a very tight home. There is generally plenty of air coming under the door and through the HVAC supply to the bathroom and the door is typically left open after the occupant finishes bathing. I recommend a humidity and timer control on the fan to ensure that the moisture is evacuated.
@@AddisonHomes It makes sense having HVAC ducting entering the bathroom for adequate make up air, I was speaking in the case of an older home as my own where there are no openings whatsoever, no window and only the exhaust vent.
Some idiotic builder didn't install a bath exhaust fan but a cheap recirculation fan instead. Can I run a 20 feet long and 3 turns exhaust duct from basement bathroom to the roof? Thanks.
Yikes! Just make sure you use solid duct and wide sweeping turns wherever possible and upgrade the fan to one that compensates for static pressure to provide flow.
Just moved into a new multilevel townhouse, my bathroom ventilation randomly just leaks a huge bucket load of water in about 20 minutes... Called the HVAC, they said we aren't touching it.. called the plumber, he said its not the pipes... Plumber told me to call a water restoration expert.. Called him, he came over and said he doesn't know where its coming from, and that he only fixes the water damage... He said I should call the HOA, since its coming from inside the ceiling... Any tips before I do that? I'm slowly starting to get water damage.
It is not exhausting the air outside and in the winter there is condensation from an uninuslated ductwork in your attic. I would look to make sure it is inuslated and is actually exhausting outside. I had this same issue and found out it was uninuslated duct work and was just dumping into my attic...not outside.
@@Makaveli6103 Ahh I see thanks.. I actually don't have an attic, but rather a rooftop deck. So is the duct somewhere between the 1st and 2nd floor? that probably means I have to open up some walls to get to it right?
Agree with the previous reply. You likely are getting condensation on the interior of the exhaust duct which is collecting, then draining back into the fan housing. Likely occuring after enough water collects in the flex duct to "dump" back down.
If a tract builder can save $20.00 on each fan they install....that will add up to ALOT of money in his pocket.......what the code people should do...is revamp the specifications as to what will do a much better job because most builders just shoot for the minimum acceptable standards in buildings.
Great point. Its big money when multiplied over thousands of homes. Unfortunately, the homeowners pay for it in the long run. This is why we emphasize that the building code is the MINIMUM legal standard for building - NOT necessarily the BEST standard, unfortunately!
I would say only if you have high ceiling at least 2 ft above shower head and yes use a gfci outlet due to it will trip the circuit(turn off) should water enter the electric part of vent fan. Safety first
To avoid humidity in bathroom 1 Don’t run long duct runs 2 avoid poor, cheap airfans 3 avoid small diameter ducts 4 flexible ducts runs instead of hard pipe runs
First, Fan selection - you can't go wrong with any bath fan that compensates for static pressure loss using an ECM (DC) motor - Panasonic offers many. None of these will use a duct smaller than 4" in diameter. Second, minimize the length of the duct run to outside, and use hard metal duct unless the run is less than 6 feet or so.
@@AddisonHomesnutone makes some great fans that go up to 110 cfm great for bathrooms 95 sq ft or under. Many builders choose inadequate sized fans coupled with bad ductwork for the space and it’s really odd.
@@charlesrodriguez7984 No doubt! We prefer to use the pressure compensating / selectable airflow DC fans from Panasonic. In standard small bathrooms, we use the selectable 50-80-110 cfm model with a 4" duct and in larger bathrooms (owners bath typically), we use the 110-130-150 selectable model with a 6" duct. Its always best to duct with hard metal duct then transition to a short section of flex if necessary at the end. We've not had any issues for years with these pressure compensating models getting enough airflow. Many builders use the "builder grade" fans that make more noise than airflow! I've never understood why other than "its what they've always used".
@@AddisonHomesIn fact they installed a cheap 60 cfm 4.0 sone nutone fan In my bathroom that I replaced with a Hampton bay fan 2.0 sones and 70 cfm(it even looks similar to the cheap nutone fan). Quite the upgrade compared to the old fan. The ones in my master are much better despite being a similar cheap exhaust fans. I 100% agree with this video.
It depends on the specific version of the code adopted in your local area but the 2018 International Residential Code requires and exhaust fan of 50 cfm intermittent or 20 cfm continuous in toilet rooms. Hope this helps!
Fluids are materials capable of flowing and easily changing shape. The most familiar natural fluid is water. But air is considered a fluid as well! No need to grow gills!
Ya that run is way too long. But you don't mention the CFM of the fan. You use marketing terms to call the fan "small", "undersized", "inadequate". Bathroom needs minimum 1cfm per sqft. It's simple math. CFM of fan, divided by bathroom size. Numbers matter.
The 1 cfm per sq ft could be used as a rule of thumb, but we prefer to exceed the guidelines in the EPA's ENERGY STAR standard by using selectable airflow pressure compensating exhaust fans in bathrooms that give us a selectable range of 80 cfm to 150 cfm depending on the size of the bathroom. The key, in our opinion, is to test the fans for airflow at commissioning, and to use a condensation sensing timer switch to control the fan, so that it runs for a minimum of 60 minutes and anytime there is high humidity resulting in condensation potential. In all honesty, smaller bath fans that are tested for flow will suffice when controlled by a condensation sensing timer switch , but the larger fans will remove moisture more quickly resulting in benefits such as the mirror not fogging for so long after a shower.
How do you feel about venting directly through the roof above the fan? I currently am struggling with an inadequate bathroom vent fan over the shower. When we had a home inspection done it was discovered they had vented it directly into the attic above and caused mold up the rafters. So part of the buyers agreement they had to do mold remediation and vent the bathroom out of the attic. Well I discovered they had run 30' of that soft across the attic and out the back side of the house wall. It was fine for the first couple of years but now I'm struggling with it not really venting and now mildew developing. I am looking at vent fans pushing 110CFM (Panasonic was one of them) but I still don't feel like with 30' of vent tube that would be strong enough to vent it that far without a fan in the middle to help push it all the way out. I am thinking about a vent directly up through the roof but am nervous about the potential of water issues/damage if not done properly.
Makes complete sense. You can certainly vent through the roof if it is more direct and a shorter run. The roof cap selection is important to minimize resistance to flow. I recommend Primex RV20 or RV28 roof vent caps. You could also change your vent fan ducting to rigid metal duct as far as possible, then transition to flex duct at the very end where it vents through presumably the soffit, however, a 30’ run will do better with a Panasonic Whispergreen 110-130-150 selectable fan that uses a 6” duct and will definitely move more air. The 6” duct dramatically reduces resistance to flow at those ventilation rates and can work through the roof or through the soffit (if there is enough space).
We often vent up through the roof of the only alternative is to run that far. Not a problem if installed into the roof correctly. I recommend the Primex RV20 or 28 roof vent cap. It has a nice adapter for a positive connection and a damper. You are correct that even the best Panasonic whisperGreen fan won’t push much flow through 30’ of flex duct. You’ll probably notice a substantial difference going up through the roof with a much shorter run.
@AddisonHomes I have a question? If I have 2 bath vents , do I need 2 roof vents if they are close to one another in Attic? Thinking insulated on both vent pipe straight up as possible into a tie in box made for 2 pipes joining into 1 roof vent ?????
@@AddisonHomes could've elaborated by showing what was there, how to properly do it. Explain what the sizing is by 1 CFM/sq ft (50CFM minimum) and how to properly exhaust it out of the roof or side of home. How to run the duct work (don't put and 90 degree angles in the flex duct) ya know, basically everything.
Yes -- best practices -- the thing codes don't always point to. So many builders are merely installers, and they either do not think or do not care. The irony is that there's a millions ways to balloon a house's cost, and they can often save money in ways that don't matter. A bath fan is noticed EVERY DAY.
Kudos for somehow being able to get into a computer's new construction to point this out.
I often remind folks that the building code is the MINIMUM LEGAL standard for construction - and doesn't typically incorporate the latest best practices. Not to mention, most building inspectors are experts on the CODE, not best practices, and they often have so many inspections to do, they cannot possibly catch everything.
This video was extremely helpful! Thank you so much. Our house here in Texas was built in 1994. There is no exhaust fan at all in our primary bath. There is a window in the toilet area so maybe that's why? Maybe no code for it in our area back then? Not sure, but we are remodeling our home and considering putting in an exhaust fan. This video has been very helpful to make sure our contractor veers towards best practices. Thanks!
So glad it was helpful!
Lazy contractors here in the northeast can follow ‘code’ and neglect an exhaust fan as long as there is a window in the bathroom. Yup, ice cold air is so nice when you’re getting out of the shower plus, of course, it does wonders for privacy. And windows don’t necessarily vent well. No wonder folks despise contractors.
Sad but often true.....
Many areas no longer allow just a window for that reason. They require a fan with or without the window.
Excellent video. I am replacing my original builder provided low CFM and high noise fan. Now I see how cheap it is and the exhaust is vented on flexible aluminum hose.
Glad it was helpful!
My bathroom needs a resturant vent fan for my bathroom😂😂
You are absolutely right that long narrow flex duct has the most resistance of air flow and by the time air flow reaches to the outside there’s probably nothing left to exhaust.
It’s useless to even installed it.
The classic "noisemaker", not ventilator.
Well what happens is the turbulence in the exhaust causes the moisture to have allot more time to condensate. Flex duct is supposed to be stretched with 2 people holding it tight for a few minutes.
Heres the most important to note, when you lay any vent pipe flat across attic your moisture( water) is collected in the pipe and thats where 60 percent stays. 40 percent is infused into nearby insulation and some in attic air. Hence the water stain that will be on your ceiling below and eventually bubble warping out as moisture continues. Eventually that part of ceiling will fail becoming mushy swelling.
TRUST ME, we did the long flex pipe laid horizontal across attic prob 20FT +
WELL, that was probably about 5 yrs ago now ive had a stain my kitchen ceiling for about 2yrs +. I thought it was a roof leak. Well turns out that flex pipe laid horizontal across attic.....here goes had about 1/3 full mop bucket of just water in its bows and lags of vent pipe. In which the moisture that did reach the end of pipe was soaking insulation and ceiling. Though it was a small area 6" pipe it has spread to 12" area on ceiling before i went in attic and found the issue. With someone on ladder holding bucket below attic entry we carefully dumped a huge ton of water out into a huge mop bucket. It filled it 1/3 the way. Of course being careful when raising flex house to dump , as not to let water flow back to vent fan in ceiling. Could you imagine ......ih never again! vent straight up through roof with no lag back down.
Now that i just found tjis 1 day ago weve got our work to do roof vent do it right DIY. RESEARCH HOW ITS DONE CORRECTLY
We are planning to have a metal roof installed. The roofer recommended we remove and relocate our roof penetrations. This includes a 4” plumbing vent stack and our bathroom exhaust. Our home has a conditioned attic. I have a Broan Nutone 110CFM exhaust. I would like to vent out the gable end. That distance is about 25’. If used a rigid 3” vet would I be successful in eliminating the humidity? If necessary could I add an inline pressure sensitive fan along the run to help move air more efficiently. Thoughts?
Depends on whether the Broan 110cfm is pressure compensating. If it isn’t, you can always run rigid 6” duct to a 6” sidewall vent which would minimize pressure drop across the 25’ run. Or, you could replace the existing fan with a pressure compensating model and duct with 4” rigid. Do you have a humidity issue now?
So I have an older home with 2 bathrooms right next to each other but I have no fan in neither bathroom, I want to install a fan in both bathrooms but I’m also installing solar panels on the same side and my question is can I install the roof vent next to each other’s side by side or above each other?🙏
You can definintely install the roof vents side by side. Do you have the ability to run the vents out through a soffit or side wall of the attic?
@@AddisonHomes i dont but I installed it one above the other one with 4’ between. Thank you for the response
Ill never forget when i built my house (2008) i found the box my bath fans came in. It was $13.88 at HD with 3 inch flex duct. It can't hold a tissue.
Sad but so true! They are best used as noise makers!
@@AddisonHomes
Fart box
Our builder refused to use anything other than flat paint in our bathrooms which was wild to me. Flat paint ceilings and walls and a 50 cfm fan in the 100 sq ft bathroom.
The day we moved in we painted all the bathrooms walls and ceilings with satin so at least that's better. It's a huge pain to replace an exhaust fan and I really don't want to walk around on ceiling joists to do so but I do need to go up there and see what pipe they used. I would bet it's the cheapest they could get -_- Once I get caught up on other projects I might go ahead and switch it all out to OUR higher standard.
Thats a tough situation. Any paint with Sheen requires a higher level of drywall finish and is much more difficult to touch up. If they had only used a good bath fan with optimal ductwork, flat paint would have been fine.
Im remodeling my bathroom right now. Homedepot sells a exhaust kit but its a flexible cheap duct. I ended up installing hvac metal jacketing and some hvac 90s came out real good. But just to do about 5 ft of the good stuff was about $100.
So.. you didn't really elaborate on what exactly those best practices are or should be for a bathroom exhaust fan..
Best practices - 1) A bath fan that is rated for an adequate airflow for the space, 2) bath fan that uses a minimum 4" diameter duct, 3) A bath fan that compensates for pressure loss in the ductwork, 4) use rigid duct, 5) minimize the duct length, 6) vent to the outside
@@AddisonHomes "A bath fan that is rated for an adequate airflow for the space" How would we know what is best rated for that space? Is there a guide on this? What is recommended?
OMG this guy does a great video. Hits all the points. It is up to you to figure what is needed from this take away
@@ericlaido just wondering how you find that info?
@@AnthonyPerez The 2021 international residential building code requires that bathrooms have a minimum continuous ventilation rate of 20 cfm or an intermittent rate of 50 cfm. HVI, the Home Ventilating Institute, recommends a ventilation rate of 8 air changes per hour which typically equates to 1 cfm per square foot of bathroom area. They further suggest the following guidelines:
Bathroom less than 50 sq ft: 50 cfm fan
Bathroom between 50 - 100 sq ft: use the rule of 1 cfm per 1 sq ft of bathroom area.
Bathroom over 100 sq ft: Add the cfm requirement for each fixture - toilet (50cfm), separate shower (50 cfm) separate tub (50 cfm), jetted tub (100 cfm)
www.hvi.org/resources/publications/bathroom-exhaust-fans/#:~:text=Ventilation%20rates%20based%20upon%20eight,minimum%20for%20bathrooms%2050%20sq.
We opt for a minimum of 80 cfm in a typically sized bathroom and a minimum of 110 cfm in an owners bath or "larger" bathroom. We use exhaust fans that are selectable between 50-80-110 cfm and duct with a 4" duct for smaller bathrooms and models that are selectable between 110-130-150 and duct with a 6" duct for larger bathrooms. We run our exhaust ducts using hard metal duct to the termination if possible, allowing for a short section of flex duct at the end if needed to make the termination cap connection.
Wonderful skills in your teaching and educating! Thanks for the tutorial!!
You're very welcome!
Hi i’m thinking of buying Panasonic Whisper exhaust fan it’s 100-110 cfm. What type of duct should i use? it goes right outside my house from the attic to the roof. how many inches should the duct be?
@@Rayan-rw3gt the Panasonic fans in that range are typically 4” diameter.
@ should i use flex pipe? or rigid? does it have to be insulated
@ my hood vent in the roof is full of water drips and condensation. how can i get rid of this?
@ 1) make sure it’s air tight where it passes through the attic 2) ensure it has a damper at the roof termination, 3) adamper at the hood is helpful too.
If this doesn’t solve the issue, insulate the pipe in the attic.
@@Rayan-rw3gt rigid is best for as much of the run as possible. You can transition to flex at the vent cap. Shouldn’t have to insulate it but if it’s running through the exposed attic like your range hood, that would be a good idea.
Thank you! Does Addison Homes fix Condos? Mine is awful.
We will consider any project that aligns with our goals of achieving a higher-performance building that provides improved air quality, energy efficiency, and durability!
Can 2” or 3” direct short run to outside wall pvc pipe be used for my bathroom vent fan?
@@stonebody I’ve used PVC before to provide a low static smooth vent pipe, but never less than 4”
Thanks for your input
The pipe and size is just fine for exhaust. Those restroom exhaust fans don’t move enough cfm’s to be restricted. Only issue on that setup is the length of it
These are the problems - the exhaust fans used are not designed to move adequate cfms with any length of duct. Best practice is to use bath fans designed to adequate airflow even at elevated static pressure from longer duct runs such as those made by Panasonic and Greenheck.
Is there a reason why you would run the duct 30 feet across the house instead of going through the roof?
Likely to eliminate a roof penetration and possibility of a leak.
As a air balancer we see these issues all the time and the tin guy putting a screw or by misalignment stops the flapper opening
So true! I've seen it so many times and typically discover it when testing the exhaust fan airflow! So many don't understand why its important to test airflow. Its the only way to know if you have a problem before mold begins to grow on the walls!
Lmao when I saw that long length of flex duct I seriously thought wtf. That was insane
Sad but true!!!!!
@@AddisonHomesin the codes there should be a minimum duct run distance of 17 feet and fans that use more than 50 cfm for larger spaces. Current codes are a bit bad for building great homes with proper ventilation.
Don’t you mean “maximum” ?
excellent information and well explained.👍
Thanks very much!
So I have been working with a local HVAC company on venting my two bathrooms in a home we recently bought built in 1980. one of the bathrooms had an existing fan but it was just exhausting into the attic. The other smaller bathroom maybe 40sq feet its the shower surround and toilet, the sink is in the vanity area outside of it, had no fan and only a small window. So I had them replace the ceiling light fixture with a Broan HD80L and they were going to run both of those vents to soffit. Well I noticed they hadnt actually run them to any kind of vent on the soffit and when I asked they were like 'oh we just hang them up near the soffit' and didnt seem to understand that with the lack of a sealed vent to the exterior more than 3ft from any other intake point on the house that this wasnt code...
So they came back today and I had them run them to gable end which they completely butchered as well... they didnt install the vent screen/baffle kit correctly and installed them to close so one over lapped, then I look in the attic and they are using the cheap vinyl dryer vent type hose and instead of cutting some out because the pieces were too long they coiled it up and connected it... like this lil 80cfm fan is gunna be able to push air past that. The other one the ran it up and over a collar tie creating a big sag but also a 90 degree turn in the hose.
I spoke to the owner and he said he is going to make it right and come back and fix it. Where the fans sit lower than the gable roof vent, where we have them run to hard piping will be very difficult. But living in SC should I tell them to use insulated hose? our winters are pretty mild and I doubt the attic sees more than 3 or 4 days a year of sub freezing temps. We do get plenty of hot days tho...
Insulated wouldn't be a bad idea if they are exposed above the insulation in the attic. Even though we don't get sub-freezing temps, a vented attic is typically cool enough to result in condensation on the inside of the bath ventilation duct. Anytime in the "cold" winter, that warm, humid air on the inside of the duct venting from the bathroom after a shower is going to condense on the interior of the duct. If the duct runs up hill from the fan, you have the possibility of the condensate (water) running back and dripping into the bathroom through the fan.
I share your pain with trying to get them to install these the "right" way! It would be interesting to see what the actual flow rate is through the duct as they have it connected now!!! Keep fighting the good fight!
It's to the point that 99 percent of
Home repair, electricians, construction, doctors,lawyers, mechanics etc! They fail to do it right, Really! You have to research yourself how exactly all work is done the right way or get a half ass job done for you, that is a disaster waiting to happen or a complete and obvious fail on your dime and damages. Workers don't seem to care to learn correct way to do anything. It's a get er done mentality and as long as I get my money and the face presentation of job looks good, these people don't know anything about this kind of work so sorry for their luck! That's the mentality. Good enough to get paid and whoa to the clients
@@hcompton8861 I walked my wife through how it needed to be done and had her go up and knock it out. I am 6'1 350 and getting around in the attack is tight so the back end of the attic past all the pre made trusses is pretty inaccessible to me. But she ran with it and it looks 10x better than the 'professionals'
I had a back and forth with the owner of the company and he ended up waiving about 40% of the bill, because they did provide some materials and did get the new condensate drain hooked up.
But yeh... never trust ppl and always double check their work
Interesting. Contractors are just always trying to save a nickel here and a nickel there. How much cost would a better fan add to each unit? A couple of hundred dollars?
Yes, if that!
I was watching your show about bathroom fans. I would like to know what size of bathroom fan, I should be using for a replacement. I want to replace the bathroom fan because it creates a lot of moles and causes the dry wall and stub to deteriorate. I hope you were able to help me solved these problems
I prefer using bath fans that will move no less than 80cfm once installed. This generally means installing an exhaust fan rated at a higher airflow (say 110 cfm) and that compensates for pressure drop in the exhaust duct. Panasonic, Broan, Greenheck, and others make exhaust fans that meet these requirements.
If you have a 3" exhaust hose, can you use a an adapter for a fan with a larger hose connection?
If they are available sure but why would you want to take a 4" down to a 3" hose? Also, if you're asking is it OK as in will the fan function correctly I would say no. It's 4" for a reason. That's my opinion.
You can, but the static pressure resistance from the 3" duct will likely keep the fan from performing as designed. Going bigger is not an issue, but ducting smaller than the outlet on the fan is generally a likely failure.
I just had a new roof installed and the roof vent flap has about a 1/8” gap causing debris to get into the bathroom fan cover and floor.
What type of debris is getting in?
I need help. My bathroom extractor vent starts to drip brown liquid every few months. My house is new. Bought new in 2022. I have to take it apart and clean it twice a year. What can I do to prebet this from happening? Under the cover there are small dials for time and H% which I assume is humidity. Can adjusting these dials help at all?
I am not sure about those dial options BUT we are told to clean our exhaust fans and should be doing so. Now, why yours would drip does seem like a problem and that would worry me at least a little.
Great video!! Very informative
Thanks much!
Another factor not mentioned is make-up air into the bathroom. There should be a minimum 1/2" gap at the bottom of the bathroom door to allow air from the home to ingress and replace the air being exhausted by the fan. Failure to do so will result in a lower pressure in the bathroom that will reduce the fan's effectiveness no matter how large the vent pipe may be.
@@mrmrlee bathroom makeup air is rarely an issue, even in a very tight home. There is generally plenty of air coming under the door and through the HVAC supply to the bathroom and the door is typically left open after the occupant finishes bathing. I recommend a humidity and timer control on the fan to ensure that the moisture is evacuated.
@@AddisonHomes It makes sense having HVAC ducting entering the bathroom for adequate make up air, I was speaking in the case of an older home as my own where there are no openings whatsoever, no window and only the exhaust vent.
Some idiotic builder didn't install a bath exhaust fan but a cheap recirculation fan instead. Can I run a 20 feet long and 3 turns exhaust duct from basement bathroom to the roof? Thanks.
Yikes! Just make sure you use solid duct and wide sweeping turns wherever possible and upgrade the fan to one that compensates for static pressure to provide flow.
Just moved into a new multilevel townhouse, my bathroom ventilation randomly just leaks a huge bucket load of water in about 20 minutes... Called the HVAC, they said we aren't touching it.. called the plumber, he said its not the pipes... Plumber told me to call a water restoration expert.. Called him, he came over and said he doesn't know where its coming from, and that he only fixes the water damage... He said I should call the HOA, since its coming from inside the ceiling... Any tips before I do that? I'm slowly starting to get water damage.
It is not exhausting the air outside and in the winter there is condensation from an uninuslated ductwork in your attic. I would look to make sure it is inuslated and is actually exhausting outside. I had this same issue and found out it was uninuslated duct work and was just dumping into my attic...not outside.
@@Makaveli6103 Ahh I see thanks.. I actually don't have an attic, but rather a rooftop deck. So is the duct somewhere between the 1st and 2nd floor? that probably means I have to open up some walls to get to it right?
Agree with the previous reply. You likely are getting condensation on the interior of the exhaust duct which is collecting, then draining back into the fan housing. Likely occuring after enough water collects in the flex duct to "dump" back down.
If a tract builder can save $20.00 on each fan they install....that will add up to ALOT of money in his pocket.......what the code people should do...is revamp the specifications as to what will do a much better job because most builders just shoot for the minimum acceptable standards in buildings.
Great point. Its big money when multiplied over thousands of homes. Unfortunately, the homeowners pay for it in the long run. This is why we emphasize that the building code is the MINIMUM legal standard for building - NOT necessarily the BEST standard, unfortunately!
Amen
Can I add an exhaust fan duct to an existing dryer ventilation duct?
Could be possible, but would depend on the duct layout.
Wow. Common sense is so uncommon these days. Thanks bro 👍
No problem 👍 Glad you enjoyed!
Thank you for this video
Glad you found it helpful!
Thank you for your videos!
You’re so welcome! Glad you find them useful!
Can i put the bath fan in my glass shower?
You sure can - just make sure it is wired on a GFCI circuit
I would say only if you have high ceiling at least 2 ft above shower head and yes use a gfci outlet due to it will trip the circuit(turn off) should water enter the electric part of vent fan.
Safety first
To avoid humidity in bathroom
1 Don’t run long duct runs
2 avoid poor, cheap airfans
3 avoid small diameter ducts
4 flexible ducts runs instead of hard pipe runs
Noooooo to the flexible duct runs instead of hard pipe. HARD PIPE is going to have the LOWEST resistance to airflow = highest bath fan airflow.
Super helpful thank you!
Glad it was helpful!
Noise makers? I thought they were called "Fart Fans". Its a feature.
So what do I shop for?
First, Fan selection - you can't go wrong with any bath fan that compensates for static pressure loss using an ECM (DC) motor - Panasonic offers many. None of these will use a duct smaller than 4" in diameter. Second, minimize the length of the duct run to outside, and use hard metal duct unless the run is less than 6 feet or so.
@@AddisonHomesnutone makes some great fans that go up to 110 cfm great for bathrooms 95 sq ft or under. Many builders choose inadequate sized fans coupled with bad ductwork for the space and it’s really odd.
@@charlesrodriguez7984 No doubt! We prefer to use the pressure compensating / selectable airflow DC fans from Panasonic. In standard small bathrooms, we use the selectable 50-80-110 cfm model with a 4" duct and in larger bathrooms (owners bath typically), we use the 110-130-150 selectable model with a 6" duct. Its always best to duct with hard metal duct then transition to a short section of flex if necessary at the end. We've not had any issues for years with these pressure compensating models getting enough airflow. Many builders use the "builder grade" fans that make more noise than airflow! I've never understood why other than "its what they've always used".
@@AddisonHomesIn fact they installed a cheap 60 cfm 4.0 sone nutone fan In my bathroom that I replaced with a Hampton bay fan 2.0 sones and 70 cfm(it even looks similar to the cheap nutone fan). Quite the upgrade compared to the old fan. The ones in my master are much better despite being a similar cheap exhaust fans. I 100% agree with this video.
It is good educating presentation.
Thank you! Glad it was helpful!
it's obvious however instead the fan it doesn't have a lot of knowledge of the future issues
What is the code for a small bathroom with sink and toilet only? Is a vent required?
It depends on the specific version of the code adopted in your local area but the 2018 International Residential Code requires and exhaust fan of 50 cfm intermittent or 20 cfm continuous in toilet rooms. Hope this helps!
Air is a fluid?
That’s what he said.
We had better grow some gills or we gonna drown.
Fluids are materials capable of flowing and easily changing shape. The most familiar natural fluid is water. But air is considered a fluid as well! No need to grow gills!
Once I see one of those "all-in-one" showers, like the one behind you, I know it's a budget house. So why wouldn't the fans be cheap?
Good point, however, all "all-in-one" showers are not cheap - some are high quality and will last for many, many years.
Ya that run is way too long. But you don't mention the CFM of the fan. You use marketing terms to call the fan "small", "undersized", "inadequate".
Bathroom needs minimum 1cfm per sqft. It's simple math. CFM of fan, divided by bathroom size. Numbers matter.
The 1 cfm per sq ft could be used as a rule of thumb, but we prefer to exceed the guidelines in the EPA's ENERGY STAR standard by using selectable airflow pressure compensating exhaust fans in bathrooms that give us a selectable range of 80 cfm to 150 cfm depending on the size of the bathroom. The key, in our opinion, is to test the fans for airflow at commissioning, and to use a condensation sensing timer switch to control the fan, so that it runs for a minimum of 60 minutes and anytime there is high humidity resulting in condensation potential. In all honesty, smaller bath fans that are tested for flow will suffice when controlled by a condensation sensing timer switch , but the larger fans will remove moisture more quickly resulting in benefits such as the mirror not fogging for so long after a shower.
How do you feel about venting directly through the roof above the fan? I currently am struggling with an inadequate bathroom vent fan over the shower. When we had a home inspection done it was discovered they had vented it directly into the attic above and caused mold up the rafters. So part of the buyers agreement they had to do mold remediation and vent the bathroom out of the attic. Well I discovered they had run 30' of that soft across the attic and out the back side of the house wall. It was fine for the first couple of years but now I'm struggling with it not really venting and now mildew developing. I am looking at vent fans pushing 110CFM (Panasonic was one of them) but I still don't feel like with 30' of vent tube that would be strong enough to vent it that far without a fan in the middle to help push it all the way out. I am thinking about a vent directly up through the roof but am nervous about the potential of water issues/damage if not done properly.
Makes complete sense. You can certainly vent through the roof if it is more direct and a shorter run. The roof cap selection is important to minimize resistance to flow. I recommend Primex RV20 or RV28 roof vent caps.
You could also change your vent fan ducting to rigid metal duct as far as possible, then transition to flex duct at the very end where it vents through presumably the soffit, however, a 30’ run will do better with a Panasonic Whispergreen 110-130-150 selectable fan that uses a 6” duct and will definitely move more air. The 6” duct dramatically reduces resistance to flow at those ventilation rates and can work through the roof or through the soffit (if there is enough space).
We often vent up through the roof of the only alternative is to run that far. Not a problem if installed into the roof correctly. I recommend the Primex RV20 or 28 roof vent cap. It has a nice adapter for a positive connection and a damper.
You are correct that even the best Panasonic whisperGreen fan won’t push much flow through 30’ of flex duct. You’ll probably notice a substantial difference going up through the roof with a much shorter run.
@AddisonHomes I have a question?
If I have 2 bath vents , do I need 2 roof vents if they are close to one another in Attic? Thinking insulated on both vent pipe straight up as possible into a tie in box made for 2 pipes joining into 1 roof vent ?????
So after 30 years what people find is a lousy 3 in duct. Really disappointing
Sad but true........
Looks like 4 inch in the video.
It was only 3"
Dude that sucked you didn't show any work
? What do you mean?
@@AddisonHomes could've elaborated by showing what was there, how to properly do it. Explain what the sizing is by 1 CFM/sq ft (50CFM minimum) and how to properly exhaust it out of the roof or side of home. How to run the duct work (don't put and 90 degree angles in the flex duct) ya know, basically everything.