Hey Ben , I,m an old man building my last house and although fairly knowledgable in most trades..... I knew Zip about HVAC. I really enjoy your no BS method of educating us DIYers specifically the way you explain these systems in simple terms.... and in ways I can grasp.''''' the " Why " not just the " How ".Thanks for taking the time.
Solid video man. Your insights and advice show you are pretty married to this stuff and understand it well. I just watched a video of a guy saying he has already used 7 gallons of mastic on his ductwork and still needs more... I appreciate you thinking for yourself and not just doing what the so called "experts/code books" say because I have found that its more about updating code rather than doing what makes sense. Thanks again, great vid!
Nice job Ben, well explained and the installation looks professional 👍 I’ve been in the trade for almost 40 years and judging by some of the comments, there’s still room for improvement. Keep up the wonderful tutorials.
Means the ability to carry more air quantity Yes, at the same time the air speed fpm will be slower and quieter. Here’s an example of another benefit of using a larger duct, if a person blows through a 1 foot long straw versus a 1 foot long 2 inch pipe. It will require a lot more of your lung pressure if using the straw for the same amount of air, therefore in a duct system the fan hp will not need to work as hard. Properly sizing and design if often neglected until there is an issue :(
This video is jam-packed with lots of good common sense information, such as (running interior ducting when possible, running extra ducting to provide margin for balancing the system without choking the equipment, not obsessing about sealing interior ducting, common residential duct sizing, etc.). I agree with some commentary that duct sizing should not be solely based solely on square footage. Regarding separate return supplies to each room - I would think that providing "jumpers" should work in most case - way better than providing no-return-path-at-all-other-than-under-doors (which is what was provided on many residential bedroom of the past).
Thank you for the great explanation about return air ducts. I just bought an older house and there is only one return duct in the whole house! The oldest part of the house was built in the 1920's (or earlier) and has the old lathe/plaster walls and no return air ducts in those rooms. Your explanation was very helpful to me. Now I can get some vents above the door or through the walls which will make those rooms much more comfortable. I just subscribed and will be watching more from your channel. Thanks!
Nice video, I always insulated the main duct so that condensation would not occur. Also had to use fire stop in main wall penetrations or floor to floor. More states are now using national codes instead of local and state codes. Thanks for a great video.
I too have gotten in the practice of insulating the main ducts. Noise reduction is a factor as well as the dreaded duct-condensation. It is expensive !
Insulating main trunks running in an unconditioned space (hot attic or cold crawlspace) is great. However, when the main trunk is in a conditioned space (finished basement, first floor, or attics that have spray foam on the roof deck) do you insulate it?
Aloha Bradda, I started out watching your electrical vids over a year ago & was impressed. I have been watching all of your other projects since then. All are awesome. Keep up the good work. You have a good future ahead! Aloha!
Thank you for this wonderful information. I'm so glad you mentioned the oversizing of the trunk and adding more runs than called for. I thoroughly enjoyed this walk through. Keep it up!
Wow! This video was exactly what I was looking for. Working on a new home, installing 2 furnaces and a boiler with in-floor heat. Yours was the second video suggested. Well done.
Bro what are you striving to be top dog GC? Already learned in the electrical trade, residential at least , now your schooling us on HVAC. Let me guess , plumbing videos next? One trade is hard enough to master, let alone two or more. Think I've only met 2 or 3 people in my 25 years as an electrician that can successfully retain that much working knowledge. 💪👍. Awesome work .
Jack of all trades master of none,but still better than a master of one. That is the complete quote. Most leave out the last part,but this was the original statement.
I have always used insulated flex duct as a jumper or "transfer duct" as we call it out here in cali. Flex duct does an incredible job eliminating sound transfer, as opposed to rigid duct
thank you for this very informative video! I recently got into the skilled trades sales business, and need this to help me succeed when selling the skilled construction trades! I appreciate it!!
Appreciate the time you spent on this Ben, tons of useful info. Hopefully most of it is still up to date, since the video is a few years old. I'll be using a lot of this info in the home I'm building now. Thanks!
As a licensed mechanical engineer that designed HVAC systems for 40 years, I beg of you, as a contractor, please avoid at all costs transferring return air as you have described. It rarely works well and always causes more issues with temperature control in those rooms than anything else. Especially since the thermostat is never in that room. I can’t stress it enough, please don’t do it.
Thanks for sharing your experience as an engineer. Do you recommend running equivalent sized ducting to each room for the return as there is supply? Seems like that would be the best possible option. Personally I just am not sure that dedicated return ductwork everywhere is worth the extra cost and space that it takes up. If you can use well designed central returns with a few jumper ducts and have a system that is 95% as good then I'm not sure if the extra effort is worth that 5% improvement if you know what I mean.
@@BenjaminSahlstrom I don’t have an issue with a central return for a large room. It works just fine. I will always have an issue with a transfer duct type situation. For it to work properly, the supply air has to build up enough pressure to push the air out of the room. The return air will never have enough pressure to suck it out of the room from a point return in another room. Scientifically it cannot happen. And yes, size return air like supply air. Keep in mind, the goal, especially today with residential outside air intake systems, is to have a positively pressurized house to prevent infiltration. You can’t positively pressurize a large space and then expect the return air in a smaller to to be pulled out of the room. So that room will stagnate. Love you videos!! Built my own house myself, no subcontractors, years ago. Nice to see I did pretty good. I put all my return air openings behind the doors. That way they never got blocked, ductwork just happened to be right below them so minimal cost and got great circulation in all rooms.
@@BenjaminSahlstrom I was going to say the same thing, I have only seen dedicated returns a few times in my career and there is rarely a bentonite except where a specific room has increased heat load
@@michaeldehart779 this just simply not scientifically true just because the house is pressurized from outside pressure does not mean pressure from room to room will not cause flow in a similar fashion from room to main area. As the main pressure being a lower pressure will cause the higher pressure in room to flow to equalize.
Thank you so much for a wealth of information in one video. This makes me re-think my double wide fiberglass duct replacement with a more central located. Thank you for posting! Subscribed
Glad you found it useful! Obviously it's just my opinion and there are more scientific methods that can be used (as some other comments show) but I like to find a good balance where the system works great while keeping some cost savings and practicality concepts in mind.
@@BenjaminSahlstrom The main thing is what you are doing works. I understand the comments about sealing everything to direct perfect measured flow to each zone, yet those walls are closed tight. Any place fiberglass is in the interior walls, with duct I would feel better sealing completely. I like that extra ducts and vents allow for adjustments at the vent to balance each room. The house shown, and duct work must have had pre-planning to make it work.
True except that some of the runs come off very near the beginning of the run/plenum which gets it really close to the correct velocity almost immediately. Good point though.
If you're installing new, in a new construction building with everything open, you should put a small return in each bedroom, as well as upper and lower returns that are switchable for winter and summer modes. You want to extract warmer air from the upper level in the summer, and extract cooler air from the lower level in the winter. Deliberately extracting cool air from the lower level when trying to cool the house is pointless. The only time you should do this is when only using the system as a fan/vent only.
I'm trying to heat a leaky cabin with wood stoves. One of them is a furnace addon with no furnace. It's not going well. I also want to either run some sort of forced air from an outside fire pit or liquid heat to some sort of radiator with the fan behind it underneath the cabin to heat up the cool crawl space still thinking it through wrong time of year to be doing that but this gives me an idea of where to go when the weather gets better. Like your channel a lot it's informative and gives me more ideas thanks for sharing
Hey Ben, first of all, I appreciate your videos as they helped me so learn so much! I wanted to ask you a few questions: do you build the hvac system off of plans? If so do you have a mechanical engineer that makes them for you? Or what does that process look like. I’m on a hotel project right now with a large GC so everything goes through the engineers with a shop drawing submittal process. I’m sure there are some differences with residential builds right?
For a 3 ton I normally size the ductwork around 30x8 of course it would depend on my distribution system resistance and total length and available static pressure to begin with. But typically a blower with .5 in. W.C. And a load calc that signifies 1200 CFM than my duct design would equate to around 30x8 @ 700 FPM on average through main truck 600 Fpm at runouts.
Perfect example ! This is how many guys produce their videos ! Ouch ! Do they not realize how transparent it really is. Try less to impress..... and more to impart.
Hi Ben! Quick question... I have heard that central A/C systems are really LOUD because of bends and turns in the ductwork. I visited a really silent home where they had a single run down the center of the home (it was designed that way for that reason). Now I know that's not practical on the average home, but what do you think a custom home builder should do?
First of all Ben’s video is very well done and top quality as far as I concerned. I’ve done a few myself and If I was building a custom home? I would try and plan it to keep the main truck duct straight and eliminate some air turbulence / resistance and if I have the head room I’d go with a round main truck to cut down on friction.
Wow! 21 runs for a 65k btu system and what looks to be a 4000 sq ft home. Hope that place is in a warm climate. We are in upstate NY and I have a 65k btu system for a 1000 sq ft office space with spray foamed walls and ceiling.
I bought a 3 story house the furnace in the basement thermostat on middle floor return air duct on top floor it didn’t work well at all it was either cold upstairs in winter or hot in the summer hvac went south we put in a new system switched that return air duct and let the return go down the stairs like you talked about and now the house is more balanced get rid of that return air duct like you have it
You’re forgetting the way returns work… it’s beneficial for your supplies to be a bit further away from your return so it works well and mixes with the room.
It's good to seal return duct...because the return side will draw unfiltered air into system depending where filter is located.. I like filter rack on wall...so it keeps dust out of ductwork..if filter is at furnace then it allows dust to get into the return ducts
Hi,What size did you use for supply duct? Is it same as return duct 24 by 8 for 3 ton unit? If yes isn’t too small for 3 ton unit because according to the duct calculator we should use atleast 30 by 8 for 1200 cfm.
Good tip is to use some 1" fold drives in the shape of a C or Z. Then you can have the ductwork hang an inch off the joists to prevent vibration. Also can help hanging the ductwork easier.
great vid. I would highly recommend to seal the ducts. Why, so the conditioned air i am paying for gets to where i want it. If i need more return or supply, i just add it at will. woohoo
Great video! Question for you. I'm finishing my basement, and I'm required to add an air return. Can i just cut into the existing return ductwork in the basement and add a grille?
I completely disagree with determining cfm/number of vents per room based on sq ft. Corner and bonus rooms need more heat/cooling than middle rooms. Why not use the result of a room by room load calculation and get it right? Also, sealing may not always save energy with everything in the conditioned space, but it improves comfort by delivering the air where it's needed. Cooling is more affected by this than heat. In my area, most trunk lines are in basements, and losing a lot of cooled air to the basement is problematic.
All good points and I don't necessarily disagree. I should have emphasized that rooms with significantly more exterior walls need more CFM delivered to the space. My point was that if you run about twice as many vents to each area you can fully balance the system later without having to calculate the exact amount for each space which is more complex than most individuals can accomplish. My goal was to give advice that anyone could follow and have a good system in the end even if they aren't "experts" on ductwork.
@@BenjaminSahlstrom loadcalc.net is free and now allows for room by room. btu per cfm is fairly straight toward to calculate. i think it's easier to sit down and do a little more math than physically install twice is many runs lol. but i'm not a sheet metal guy.
Ben, my understanding that not sealing the duct work, conditioned space or not affects the static pressure rating of the design of the system.I believe most installers would love not having to do it.
For this project 4K SQFT, did the customer have it zoned? If yes, then how did that affect your duct installation. Since it wasn't discussed in the video, I am assuming this was single-zone controlled. If true, then as a future video idea would you talk about a home that has zone control and how that affected the duct design. Is that simply having controlled dampers on each supply trunk servicing a zone?
I have a hard time, finding a company that knows manual j, s, t and d. The ones I call tell me. You need this size / you need that size. BTW, what are those manuals.. I ask, how did you get to that calculation. I'm told, "it based on my experience, we don't use any of the manuals." Maybe I'll get lucky finding a company online and provide them with house details. Thanks for posting. Looking forward to the next episode....
If I were heating a huge house, I would have multiple furnaces and multiple duct systems. One furnace and duct system for a given section of the house. For efficiency. Plus the added benefit of avoiding a single furnace failure in the dead of winter.
DIYer from Ottawa Canada, good stuff, but a few questions. Should be taping over the S-cleats to make a perfect seal, and should you be insulating the duct-work itself so you don't lose the heat to interior wall space? Need to know for my own/future projects.
I never put return airs in the ceiling especially in basement because all the warm air will go straight back in the return air. I recently moved return airs being in the ceiling and put them down in the wall because basement was always too cold.
Is there a formula for an air return duct size in relation to the supply size in a small sealed room? In other words I will be supplying a room with 2- 6" ducts. What should the return air size be?
I dont have any experience with HVAC but I'd say seal and insulated so you don't run the risk of dealing with what I'm dealing with. Condensation and mold between my 1st story ceiling and 2nd story floor. I have an older house though so it may not have good exterior wall insulation which could be causing the issue.
While we looking at HVAC. I have a. 240 (practical) sqrft tiny house. That started as a mobile office. Wich features a thru-the-roof style ac. Wich worked surprisingly well as long as I left the (separate) furnace fan running during the day... The roof unit has stopped blowing all together. And my "trusty" HVAC guy. Seems to think. It wouldn't be worth my money to replace a. Dual shaft motor and cap set. When a mini split or window unit (installed permanently thru a wall) would be more cost effective.... What are your thoughts.
Hello We are currently building a new house in McCormick, SC 1600 sq ft built on a slab. The hvac will be in attic. There is one return grill in the ceiling Your video here offers a lot of great ideas and cautions. Please give me the do’s and don’t’s for this type of install
Great video!! To clarify what you said about location of return air similar to in your house. For a 2k sf 3 story house, is it good to locate the return air grille in the wall near the floor of the lowest level? The furnace is in that same level
No kidding! It's actually my sister and brother in law's place down in Nebraska. They have a channel where they're sharing their story if you want to check it out. ua-cam.com/channels/5eWIbyrYcXnWzyPzy7x39A.html
I have a toilet that I’d like to relocate but the spot I’ve chosen to move it to is right above a return air duct. Can I cut a hole and run a pipe through it and then just seal it with that silver tape?
Thanks for the info..👍🏽 Question: Did you use any software/computer program for your load and design calculations ( manual J,D,S). Any input or opinions on design software?
Im a GC Building new construction homes, I know very little in HVAC but my understanding of duct sizing calculations really is breaking my head when i hear you say, you can slap an extra couple supply registers in a room as extras so they dissipate more gradually at a lower velocity. Does that not affect the whole supply design system, and the calculations that the duct system was size for. Please, look forward to your input. Looking to learn more about this trade.
1- Please tell me you did not install heat runs on the end cap?! 2- did you install turning vanes in the long radius 90's? And 3- I know how you feel about sealing ductwork in a conditioned space. But in Humid climates this helps prevent mold developing in the ductwork due to humidity and moisture combining. Unless the source of the mold is somewhere else in the house
Winter climate my preference would be to have the return air at basement floor level. Summer time my preference would be to have most of the returns pulling from upstairs high wall. You don’t want to pull all your cold conditioned air to the basement because the basement is naturally cool enough during the summer. You just need a small amount of return simply to help humidity and air quality.
Does anyone know what size rectangular ducts are needed for a 420 square foot 3 room addition? It has a separate furnace, 24 foot straight run and six 6" side vents. I got 8" x 16" supply rectangular ducts but haven't installed them yet as I'm not sure if they aren't too big.
Great video! What is the longest cross break you can have one a supply trunk? I have a 4x10 ft sheet of galvanized metal and I was thinking in making 10 feet trunk sections. Would that work?
You may disagree but seal duct so most the air will deliver to living condition spaces faster. System will shut down When temperature in living condition space satisfy consume less energy. If air leak into other space it not contributes into comfort. Those air create excessive temperature that doing nothing to the comfort of occupants but make the system run longer to satisfy the setting. Yes those hot or cold air still trap in the envelope and slowly gain or lose heat depend on temperature difference between envelop and the outside. So duct leak effect system performance and capacity
this guy looks like he's 16 years old. watched an older video of his where he looked like he was 12 and wearing a wedding band. guy must be doing something right to be able to build on this scale...
Hello friend, I have a question, if you could help me please, my question is the following: I have a two-story house, each floor is 1000 square feet and the height of each floor is 18 feet. My question: How can I calculate how many frigorias I need for my house? My question. The thing is that many air conditioning brands only give calculations for ceiling heights of 9 feet and they say that if they are more feet high the calculation is different but they don't say how I've been trying to find an answer for weeks and there isn't one and I would like an air packge unit for the whole house, my question in summary would be how should I calculate the frigories of my house by the height of my house which is too high
Hey Ben , I,m an old man building my last house and although fairly knowledgable in most trades..... I knew Zip about HVAC. I really enjoy your no BS method of educating us DIYers specifically the way you explain these systems in simple terms.... and in ways I can grasp.''''' the " Why " not just the " How ".Thanks for taking the time.
Solid video man. Your insights and advice show you are pretty married to this stuff and understand it well. I just watched a video of a guy saying he has already used 7 gallons of mastic on his ductwork and still needs more... I appreciate you thinking for yourself and not just doing what the so called "experts/code books" say because I have found that its more about updating code rather than doing what makes sense. Thanks again, great vid!
Nice job Ben, well explained and the installation looks professional 👍 I’ve been in the trade for almost 40 years and judging by some of the comments, there’s still room for improvement. Keep up the wonderful tutorials.
Bigger pipe means more air right?
Means the ability to carry more air quantity Yes, at the same time the air speed fpm will be slower and quieter. Here’s an example of another benefit of using a larger duct, if a person blows through a 1 foot long straw versus a 1 foot long 2 inch pipe. It will require a lot more of your lung pressure if using the straw for the same amount of air, therefore in a duct system the fan hp will not need to work as hard. Properly sizing and design if often neglected until there is an issue :(
This video is jam-packed with lots of good common sense information, such as (running interior ducting when possible, running extra ducting to provide margin for balancing the system without choking the equipment, not obsessing about sealing interior ducting, common residential duct sizing, etc.). I agree with some commentary that duct sizing should not be solely based solely on square footage. Regarding separate return supplies to each room - I would think that providing "jumpers" should work in most case - way better than providing no-return-path-at-all-other-than-under-doors (which is what was provided on many residential bedroom of the past).
Thank you for the great explanation about return air ducts. I just bought an older house and there is only one return duct in the whole house! The oldest part of the house was built in the 1920's (or earlier) and has the old lathe/plaster walls and no return air ducts in those rooms. Your explanation was very helpful to me. Now I can get some vents above the door or through the walls which will make those rooms much more comfortable. I just subscribed and will be watching more from your channel. Thanks!
Nice video, I always insulated the main duct so that condensation would not occur. Also had to use fire stop in main wall penetrations or floor to floor. More states are now using national codes instead of local and state codes. Thanks for a great video.
I too have gotten in the practice of insulating the main ducts. Noise reduction is a factor as well as the dreaded duct-condensation. It is expensive !
Insulating main trunks running in an unconditioned space (hot attic or cold crawlspace) is great. However, when the main trunk is in a conditioned space (finished basement, first floor, or attics that have spray foam on the roof deck) do you insulate it?
Nice job! It so nice to see someone do an install where they only use flexduct when really necessary. So many installs I see are flexduct disasters.
I always prefer "real" ductwork over flex but it does have it's place. Flexduct makes for a really quite system which is a nice benefit.
Aloha Bradda,
I started out watching your electrical vids over a year ago & was impressed. I have been watching all of your other projects since then. All are awesome. Keep up the good work. You have a good future ahead!
Aloha!
Thank you for this wonderful information. I'm so glad you mentioned the oversizing of the trunk and adding more runs than called for. I thoroughly enjoyed this walk through. Keep it up!
Wow! This video was exactly what I was looking for. Working on a new home, installing 2 furnaces and a boiler with in-floor heat. Yours was the second video suggested. Well done.
Are we related??
Bro what are you striving to be top dog GC? Already learned in the electrical trade, residential at least , now your schooling us on HVAC. Let me guess , plumbing videos next? One trade is hard enough to master, let alone two or more. Think I've only met 2 or 3 people in my 25 years as an electrician that can successfully retain that much working knowledge. 💪👍. Awesome work .
I really think he could be top dog lol, He is a Master Plumber! and I'm pretty sure he's been doing HVAC service calls since he could walk 🙃.
HVAC mechanics are masters of all the trades you mentioned!💪
Well ur around the wrong person
When your a licensed general contractor u have to know all the trades
Jack of all trades master of none,but still better than a master of one. That is the complete quote. Most leave out the last part,but this was the original statement.
The trades are easy. No where near hard. Ofcourse I'm not a doctor but thebamoubt if stuff doctors or physicist know is staggering.
I have always used insulated flex duct as a jumper or "transfer duct" as we call it out here in cali. Flex duct does an incredible job eliminating sound transfer, as opposed to rigid duct
Love your videos, Ben! Super thorough and smart. Lots of common sense mixed in with a wealth of technical know-how and experience.
I appreciate that!
thank you for this very informative video! I recently got into the skilled trades sales business, and need this to help me succeed when selling the skilled construction trades! I appreciate it!!
Good stuff, remember when air is pushed outside of the home, outside air has to enter home to make up.
Appreciate the time you spent on this Ben, tons of useful info. Hopefully most of it is still up to date, since the video is a few years old. I'll be using a lot of this info in the home I'm building now. Thanks!
As a licensed mechanical engineer that designed HVAC systems for 40 years, I beg of you, as a contractor, please avoid at all costs transferring return air as you have described. It rarely works well and always causes more issues with temperature control in those rooms than anything else. Especially since the thermostat is never in that room. I can’t stress it enough, please don’t do it.
What do yo recommend?
Thanks for sharing your experience as an engineer. Do you recommend running equivalent sized ducting to each room for the return as there is supply? Seems like that would be the best possible option.
Personally I just am not sure that dedicated return ductwork everywhere is worth the extra cost and space that it takes up. If you can use well designed central returns with a few jumper ducts and have a system that is 95% as good then I'm not sure if the extra effort is worth that 5% improvement if you know what I mean.
@@BenjaminSahlstrom I don’t have an issue with a central return for a large room. It works just fine. I will always have an issue with a transfer duct type situation. For it to work properly, the supply air has to build up enough pressure to push the air out of the room. The return air will never have enough pressure to suck it out of the room from a point return in another room. Scientifically it cannot happen. And yes, size return air like supply air. Keep in mind, the goal, especially today with residential outside air intake systems, is to have a positively pressurized house to prevent infiltration. You can’t positively pressurize a large space and then expect the return air in a smaller to to be pulled out of the room. So that room will stagnate.
Love you videos!! Built my own house myself, no subcontractors, years ago. Nice to see I did pretty good. I put all my return air openings behind the doors. That way they never got blocked, ductwork just happened to be right below them so minimal cost and got great circulation in all rooms.
@@BenjaminSahlstrom I was going to say the same thing, I have only seen dedicated returns a few times in my career and there is rarely a bentonite except where a specific room has increased heat load
@@michaeldehart779 this just simply not scientifically true just because the house is pressurized from outside pressure does not mean pressure from room to room will not cause flow in a similar fashion from room to main area. As the main pressure being a lower pressure will cause the higher pressure in room to flow to equalize.
Impressive video. You answered all the common questions and concerns for a diy install. Thank you.
Thank you so much for a wealth of information in one video. This makes me re-think my double wide fiberglass duct replacement with a more central located. Thank you for posting! Subscribed
Glad you found it useful! Obviously it's just my opinion and there are more scientific methods that can be used (as some other comments show) but I like to find a good balance where the system works great while keeping some cost savings and practicality concepts in mind.
@@BenjaminSahlstrom The main thing is what you are doing works. I understand the comments about sealing everything to direct perfect measured flow to each zone, yet those walls are closed tight. Any place fiberglass is in the interior walls, with duct I would feel better sealing completely. I like that extra ducts and vents allow for adjustments at the vent to balance each room. The house shown, and duct work must have had pre-planning to make it work.
The velocity in your return trunk on ceiling is a couple hundred feet to fast. Lot of it doesn't comply with IECC 2012 which has been out 9 years now.
True except that some of the runs come off very near the beginning of the run/plenum which gets it really close to the correct velocity almost immediately. Good point though.
If you're installing new, in a new construction building with everything open, you should put a small return in each bedroom, as well as upper and lower returns that are switchable for winter and summer modes.
You want to extract warmer air from the upper level in the summer, and extract cooler air from the lower level in the winter.
Deliberately extracting cool air from the lower level when trying to cool the house is pointless.
The only time you should do this is when only using the system as a fan/vent only.
Based
where do you place filters? If there is only one at the air handler/furnace, wont all the return ducts eventually fill with dust?
Didn't look like a Minnesota home until you showed that double stud.
This project is actually in Nebraska at a family members of mine. It's only about 3 hours from Minnesota though so still a pretty cold climate.
I'm trying to heat a leaky cabin with wood stoves. One of them is a furnace addon with no furnace. It's not going well. I also want to either run some sort of forced air from an outside fire pit or liquid heat to some sort of radiator with the fan behind it underneath the cabin to heat up the cool crawl space still thinking it through wrong time of year to be doing that but this gives me an idea of where to go when the weather gets better. Like your channel a lot it's informative and gives me more ideas thanks for sharing
Hey Ben, first of all, I appreciate your videos as they helped me so learn so much! I wanted to ask you a few questions: do you build the hvac system off of plans? If so do you have a mechanical engineer that makes them for you? Or what does that process look like. I’m on a hotel project right now with a large GC so everything goes through the engineers with a shop drawing submittal process. I’m sure there are some differences with residential builds right?
For a 3 ton I normally size the ductwork around 30x8 of course it would depend on my distribution system resistance and total length and available static pressure to begin with. But typically a blower with .5 in. W.C. And a load calc that signifies 1200 CFM than my duct design would equate to around 30x8 @ 700 FPM on average through main truck 600 Fpm at runouts.
Perfect example ! This is how many guys produce their videos ! Ouch ! Do they not realize how transparent it really is. Try less to impress..... and more to impart.
Hi Ben! Quick question... I have heard that central A/C systems are really LOUD because of bends and turns in the ductwork. I visited a really silent home where they had a single run down the center of the home (it was designed that way for that reason). Now I know that's not practical on the average home, but what do you think a custom home builder should do?
First of all Ben’s video is very well done and top quality as far as I concerned. I’ve done a few myself and If I was building a custom home? I would try and plan it to keep the main truck duct straight and eliminate some air turbulence / resistance and if I have the head room I’d go with a round main truck to cut down on friction.
Wow! 21 runs for a 65k btu system and what looks to be a 4000 sq ft home. Hope that place is in a warm climate. We are in upstate NY and I have a 65k btu system for a 1000 sq ft office space with spray foamed walls and ceiling.
I bought a 3 story house the furnace in the basement thermostat on middle floor return air duct on top floor it didn’t work well at all it was either cold upstairs in winter or hot in the summer hvac went south we put in a new system switched that return air duct and let the return go down the stairs like you talked about and now the house is more balanced get rid of that return air duct like you have it
You’re forgetting the way returns work… it’s beneficial for your supplies to be a bit further away from your return so it works well and mixes with the room.
Nice video.
Great knowledge. Thanks for sharing
No problem!
It's good to seal return duct...because the return side will draw unfiltered air into system depending where filter is located..
I like filter rack on wall...so it keeps dust out of ductwork..if filter is at furnace then it allows dust to get into the return ducts
An added cost but it does make sense.👍
Hi,What size did you use for supply duct? Is it same as return duct 24 by 8 for 3 ton unit? If yes isn’t too small for 3 ton unit because according to the duct calculator we should use atleast 30 by 8 for 1200 cfm.
Residential is .1 static pressure. Also this dudes house is never going to cool properly. He never reduced that duct once
always on topThis man is so great
Good tip is to use some 1" fold drives in the shape of a C or Z.
Then you can have the ductwork hang an inch off the joists to prevent vibration.
Also can help hanging the ductwork easier.
great vid. I would highly recommend to seal the ducts. Why, so the conditioned air i am paying for gets to where i want it. If i need more return or supply, i just add it at will. woohoo
Thank you so much for all the info ,,, more HVAC Please ...
Should be more coming!
I would love to see a house with an hvac system in the attic, such as in a 2 story house.
Door grilles instead of undercut. High level return not so good for AC. Also condensation problems at high level?
That is why some of the return air is being pulled from lower in the building. Not sure what you're referring to exactly for the condensation issue.
Great video! Question for you. I'm finishing my basement, and I'm required to add an air return. Can i just cut into the existing return ductwork in the basement and add a grille?
Sure can, I would also add a manual damper which would probably be open in the winter and closed during summer depending on home comfort.
I completely disagree with determining cfm/number of vents per room based on sq ft.
Corner and bonus rooms need more heat/cooling than middle rooms.
Why not use the result of a room by room load calculation and get it right?
Also, sealing may not always save energy with everything in the conditioned space, but it improves comfort by delivering the air where it's needed. Cooling is more affected by this than heat.
In my area, most trunk lines are in basements, and losing a lot of cooled air to the basement is problematic.
All good points and I don't necessarily disagree. I should have emphasized that rooms with significantly more exterior walls need more CFM delivered to the space. My point was that if you run about twice as many vents to each area you can fully balance the system later without having to calculate the exact amount for each space which is more complex than most individuals can accomplish. My goal was to give advice that anyone could follow and have a good system in the end even if they aren't "experts" on ductwork.
@@BenjaminSahlstrom loadcalc.net is free and now allows for room by room.
btu per cfm is fairly straight toward to calculate.
i think it's easier to sit down and do a little more math than physically install twice is many runs lol.
but i'm not a sheet metal guy.
Ben, my understanding that not sealing the duct work, conditioned space or not affects the static pressure rating of the design of the system.I believe most installers would love not having to do it.
Great information. I’m a new subscriber. Thank you for your content.
Would you recommend installing insulation around your ductwork? Does this increase better airflow?
Exterior Thermal insulation will not help airflow.
For this project 4K SQFT, did the customer have it zoned? If yes, then how did that affect your duct installation. Since it wasn't discussed in the video, I am assuming this was single-zone controlled. If true, then as a future video idea would you talk about a home that has zone control and how that affected the duct design. Is that simply having controlled dampers on each supply trunk servicing a zone?
What are your thoughts on insulating in the thermal envelope? Also, what’s the purpose the standing Seam as opposed to standard, thanks
I have a hard time, finding a company that knows manual j, s, t and d.
The ones I call tell me. You need this size / you need that size. BTW, what are those manuals..
I ask, how did you get to that calculation. I'm told, "it based on my experience, we don't use any of the manuals."
Maybe I'll get lucky finding a company online and provide them with house details.
Thanks for posting. Looking forward to the next episode....
When you put it that way, sounds like a bad disease! haha
Hello friend, your videos are good, I have learned a lot, thank you.
Glad to hear that! Thanks for being a subscriber!
If I were heating a huge house, I would have multiple furnaces and multiple duct systems.
One furnace and duct system for a given section of the house.
For efficiency.
Plus the added benefit of avoiding a single furnace failure in the dead of winter.
Great explanations and camera work
DIYer from Ottawa Canada, good stuff, but a few questions. Should be taping over the S-cleats to make a perfect seal, and should you be insulating the duct-work itself so you don't lose the heat to interior wall space? Need to know for my own/future projects.
It looks like a nicely installed system. But I’m curious..why is the supply not insulated?
I never put return airs in the ceiling especially in basement because all the warm air will go straight back in the return air. I recently moved return airs being in the ceiling and put them down in the wall because basement was always too cold.
Is there a formula for an air return duct size in relation to the supply size in a small sealed room? In other words I will be supplying a room with 2- 6" ducts. What should the return air size be?
Hi Ben, it looks really good, but don’t you have to insulate the ductwork as well?
I dont have any experience with HVAC but I'd say seal and insulated so you don't run the risk of dealing with what I'm dealing with. Condensation and mold between my 1st story ceiling and 2nd story floor. I have an older house though so it may not have good exterior wall insulation which could be causing the issue.
While we looking at HVAC. I have a. 240 (practical) sqrft tiny house. That started as a mobile office. Wich features a thru-the-roof style ac. Wich worked surprisingly well as long as I left the (separate) furnace fan running during the day... The roof unit has stopped blowing all together. And my "trusty" HVAC guy. Seems to think. It wouldn't be worth my money to replace a. Dual shaft motor and cap set. When a mini split or window unit (installed permanently thru a wall) would be more cost effective.... What are your thoughts.
Hello
We are currently building a new house in McCormick, SC
1600 sq ft built on a slab.
The hvac will be in attic. There is one return grill in the ceiling
Your video here offers a lot of great ideas and cautions.
Please give me the do’s and don’t’s for this type of install
Great video!!
To clarify what you said about location of return air similar to in your house. For a 2k sf 3 story house, is it good to locate the return air grille in the wall near the floor of the lowest level? The furnace is in that same level
Thanks again for another great video bud.
That's gonna be a nice house
No kidding! It's actually my sister and brother in law's place down in Nebraska. They have a channel where they're sharing their story if you want to check it out. ua-cam.com/channels/5eWIbyrYcXnWzyPzy7x39A.html
Hi. Can I install T connector to the pipe so the heat will go upstairs living room and in to the room in the basement
Great video 100% but I’m 80% agree with some of the stuff you said.
I have a toilet that I’d like to relocate but the spot I’ve chosen to move it to is right above a return air duct. Can I cut a hole and run a pipe through it and then just seal it with that silver tape?
Nicely explained did you zone that systems out? How many square foot was the house.? 👍
Thanks for the info..👍🏽 Question: Did you use any software/computer program for your load and design calculations ( manual J,D,S). Any input or opinions on design software?
CoolCalc is a pretty good option.
Im a GC Building new construction homes, I know very little in HVAC but my understanding of duct sizing calculations really is breaking my head when i hear you say, you can slap an extra couple supply registers in a room as extras so they dissipate more gradually at a lower velocity. Does that not affect the whole supply design system, and the calculations that the duct system was size for. Please, look forward to your input. Looking to learn more about this trade.
1- Please tell me you did not install heat runs on the end cap?! 2- did you install turning vanes in the long radius 90's? And 3- I know how you feel about sealing ductwork in a conditioned space. But in Humid climates this helps prevent mold developing in the ductwork due to humidity and moisture combining. Unless the source of the mold is somewhere else in the house
depending on the climate would a basement be better off with some returns on the ceiling?
Winter climate my preference would be to have the return air at basement floor level. Summer time my preference would be to have most of the returns pulling from upstairs high wall. You don’t want to pull all your cold conditioned air to the basement because the basement is naturally cool enough during the summer. You just need a small amount of return simply to help humidity and air quality.
Does anyone know what size rectangular ducts are needed for a 420 square foot 3 room addition? It has a separate furnace, 24 foot straight run and six 6" side vents. I got 8" x 16" supply rectangular ducts but haven't installed them yet as I'm not sure if they aren't too big.
hello Benjamin i find u video very helpful i was wondering for the bungalow around 750 sqf what size of AC unit and furnace we need ,thank u very much
Great video! What is the longest cross break you can have one a supply trunk? I have a 4x10 ft sheet of galvanized metal and I was thinking in making 10 feet trunk sections. Would that work?
You may disagree but seal duct so most the air will deliver to living condition spaces faster. System will shut down When temperature in living condition space satisfy consume less energy. If air leak into other space it not contributes into comfort. Those air create excessive temperature that doing nothing to the comfort of occupants but make the system run longer to satisfy the setting. Yes those hot or cold air still trap in the envelope and slowly gain or lose heat depend on temperature difference between envelop and the outside. So duct leak effect system performance and capacity
Bro how smart are you my my guess you did hvac and learned a little bit of everything but damn
16:08+ and 19:38+…should there be gaps around the boots when installing? If so, will there be a loss of air or heat?
What happens if a full tab takeoff (19:26+) has several curves? How does this affect the air and heat flow coming out?
Would it help to wrap the attic ducts with insulation?
Well done!
Awesome video!
Thank you.
If you wanted 60 cfm average for each supply runs than why didn't you install 5" duct? I assume you have dampers at the 6" take offs to adjust for?
Subscribed you have some great content.
Thanks!
Can you make a video that compares a few common flex duct brands. Maybe include what can be found at big box stores vs HAVC supply houses.
Am about start doing this what is an good pointer to start and what to do
Ilove ductwork😍
thanks for the video
Is there a flange that goes on the backside of the drywall for the circle vent?
Great video
How do you insulate the duct with it that close together?
this guy looks like he's 16 years old. watched an older video of his where he looked like he was 12 and wearing a wedding band. guy must be doing something right to be able to build on this scale...
What happened if there’s a dent in the ductwork in the wall? How does this affect airflow?
All those extra vents add static pressure. What’s your TESP?
Nice 👍
Hello friend, I have a question, if you could help me please, my question is the following: I have a two-story house, each floor is 1000 square feet and the height of each floor is 18 feet. My question: How can I calculate how many frigorias I need for my house? My question. The thing is that many air conditioning brands only give calculations for ceiling heights of 9 feet and they say that if they are more feet high the calculation is different but they don't say how I've been trying to find an answer for weeks and there isn't one and I would like an air packge unit for the whole house, my question in summary would be how should I calculate the frigories of my house by the height of my house which is too high
Should your return be the same size as the supply?
Does transfer air duct require beads or crossbroke?
Any tips on how to learn the trade like you do?
Good info.
Please make one more video on Return Duct Routing, in actual sites.
Doing well Benjamin just need some insulation. Where are you out of? I'm in NY.
27:34 Good stuff
Your video is very helpful by the eay
Cfm's lost by not sealing connection's ; will not past code's.