I did this for my house. Put a 6 inch outside air duct right into my AC plenum on the intake side. It runs through a filter, and there is an in line fan that I hooked up. Fan is wired to turn on only when the AC fan turns on. We used to have dust covering everything in the house every 2 days... now we barely ever have to wipe off the bookshelves. It's a real game changer if you get allergies in your house.
Curious regarding your in-line fan, wouldn't it be enough to just connect the direct to the air intake since the suction provided by your furnace already provide the suction required?
@@shoebh.3389 , Yes it would already be good for getting fresh air into your house to just connect a fresh air duct into your intake plenum and leave it at that. However there's another problem going on in houses with AC ducts in the attic... The problem is the imperfect seals between the attic space and the living space. When there are pressure differences the dirt and dust from attic will drop down into the living space through the cracks and holes in the ceiling. The extra benefit of adding a fan to an outside air duct is a very small positive pressurization of the ducts and the living space. It's extremely dirty and toxic materials in most attics. The positive pressurization can be enough to stop attic air infiltration. In the case of my house, due to the extremely large attic space volume (we have steep roof with 20' tall peak attic) the pressure difference due to wind and temperature differences between attic and living space can get quite substantial. So adding that fan and pressurizing the living space was very important for us.
@@tkmair6559 That makes sense in your case. I don't have ducts in my attic and my furnace is high efficiency (i.e. dedicated fresh air intake already), so my incremental fresh air into the air plenum (without fan) should theoretically make a net-positive air pressure, wouldn't it?
@@shoebh.3389 sure, if you don't have a dirty air problem, pressurization is not really needed. I an guessing you may have tye hvac system in basement?
Ive spent half the day to find something so simple that you explained, I want to add this kind of thing direct to the furnace which i think will also clean the circulating air with clean air as my wife is a smoker, now I know its not exactly a verner hvr or hvak whatever you call them , they are difficult to install retrofit in my older home but your simple system could somehow be tweaked to accomplish this , so at least Im more informed on how to do this thanks again good job
Should've mentioned to keep an eye on that intake, didn't think of it after I bought my house in the spring, now I checked it and it was half plugged up, been trying to find a video on how to adjust the weighted part correctly and how to know it was done right? Thank you for your videos. (MN)
Move the weight until the baffle stays open. Then slide the weight a little at a time until it just shuts off the baffle. Just a touch heaver than zero gravity.
Found water heater back drafting when a.c. is running. No exhausts fans running. Problem seems to be leaking duct work in crawl space on the supply side. Causing house to be in a negative pressure.
I have a closed combustion (high efficiency) furnace and a atmospheric (top vent) hot water tank in the same room. I have experienced backdraft at the hot water tank vent when running dryer/range hood. I want to move the existing make-up air duct in the furnace room (in a bucket) to the air intake of the furnace to better support the other house equipment (dryer, range hood, etc.) and open a air register in the furnace room to support the hot water tank. I run my furnace fan 24/7. Will this work?
If the furnace is closed combustion it should have 2 pipes to the outside. One for combustion to go out and one for intake air to supply the furnace. It should not be using any house air. The hot water tank only pipes exhaust out but uses house air for combustion, creating negative air. Your makeup air supplies the hot water tank, not the furnace, which maybe isn’t piped for incoming air. Your makeup air in a bucket also supplies air to the dryer. A big user of house air. All that being said you need a mechanical contractor to answer this issue in person.
But if you are getting this fresh air from outside which is cold air, doesn't that mean you can now have this cold air not getting warm enough when passing through the furnace?
It will get heated if the furnace is running, I do get an occasional chill but not for long. It is more important to prevent negative air from entering through cracks and voids.
I think it is a higher tech version of what I’m doing low tech. Because it brings in fresh air and exchanges the heat or cool that’s in the house to the air coming in. I believe it will allow more air to come in then what’s going out because it’s not positive displacement. The main purpose of my video is to let the house that has negative air caused by dryers and exhaust fans to be brought in the house in a controlled manner instead of through cracks in windows and doors.
Hello. Thank for the tips. Do you recommend the method to connect duct to return air plenum or run a duct down into the furnace room into the 5 gallon bucket? Or both methods ?
I actually have both, a combustion air feed into my dryer (because my furnace and hot water tank are both closed combustion) and a second makup air to the cold air return on the furnace, which supplies kitchen and bathroom exhaust fans.
Hello again. I am adding a combustion air duct and I’m wondering if the inlet location on the exterior of my home can be 7ft away from a dryer exhaust vent
sorry, I do not want the MAKE UP air supply attached to the cold air RETURN DUCT. I want it into the ROOM where the furnace and clothes dryer are/is located. (water heater also) Why you ask? Combustion air as well as fan blown air. SOLUTION, Open a BASEMENT WINDOW. works well all winter comment please.
My editor, who is a little rough at times, removed the part where I show a duct of outside air coming down into a bucket, which acts as an air trap, which is in the mechanical room, supplying the dryer, and the furnace and the hot water tank, which is more controlled than letting free airflow through an open window.
Absolutely the wrong thing to do is run that to the cold air return. That needs to go to a sealed box around the burners. Sending to the cold air return is just going to make that air colder and take more to heat it up. I can't believe someone would do that.
Debatable.. just think for a sec ..that duct is in place for on demand VOLUME of air being requested by the fan immediately..what u talking about is supplying oxygen to have efficient burn..but that isnt eating up Volume of air and definitely not vacuuming it suddenly ..the biggest VOLUME of air being displaced and suddenly which creates imbalance in pressure and if air isnt available immediately to supply and balance the extra amount needing at that moment what happens?...its vacuum, negative pressure..so water heater open flue pipe is the easiest target rather than your fresh air in a box.. everything else doesnt move that volume of air in the house in an instant..furnace designed for example 1700sqft of volume to handle oppose to 5 lil burn chambers,or a 3sqft dryer slow and steadt gojng pumping out maybe a 100th of fraction of air and steady..etc.. air has resistance in volume plus duct plus return grilles ..just think why airplanes go so high?..not because they cool,or they just smoked one..less resistance.. to add more sensible reasoning to your noise..god bless everyone
@@MrEuroWolfie The reason to use outside make up air is to plumb it to the burner so when it is burning it isn't pulling a vacuum on the house and then cold outside air is sucked in through doors, windows, and cracks which then must be heated. The burner will also have a good supply of oxygen rich cold air for a better hotter burn. The greatest majority of houses have no setup like they put in and there is no issue with sucking down the flue pipe. The fan kicks in and pulls air from the cold air return and will push it through the ducts to the registers. It's a closed system more or less. The only time air would come down the flu is when a large volume of air is being sucked out of the house by a exhaust fan.
Just OPEN A WINDOW in the room/basement where clothes dryer, furnace and water heater are located. PROBLEM SOLVED. makeup air for COMBUSTION and fan driven air. comment please
I did this for my house. Put a 6 inch outside air duct right into my AC plenum on the intake side. It runs through a filter, and there is an in line fan that I hooked up. Fan is wired to turn on only when the AC fan turns on. We used to have dust covering everything in the house every 2 days... now we barely ever have to wipe off the bookshelves. It's a real game changer if you get allergies in your house.
Curious regarding your in-line fan, wouldn't it be enough to just connect the direct to the air intake since the suction provided by your furnace already provide the suction required?
@@shoebh.3389 , Yes it would already be good for getting fresh air into your house to just connect a fresh air duct into your intake plenum and leave it at that.
However there's another problem going on in houses with AC ducts in the attic... The problem is the imperfect seals between the attic space and the living space. When there are pressure differences the dirt and dust from attic will drop down into the living space through the cracks and holes in the ceiling.
The extra benefit of adding a fan to an outside air duct is a very small positive pressurization of the ducts and the living space.
It's extremely dirty and toxic materials in most attics. The positive pressurization can be enough to stop attic air infiltration.
In the case of my house, due to the extremely large attic space volume (we have steep roof with 20' tall peak attic) the pressure difference due to wind and temperature differences between attic and living space can get quite substantial. So adding that fan and pressurizing the living space was very important for us.
@@tkmair6559 That makes sense in your case. I don't have ducts in my attic and my furnace is high efficiency (i.e. dedicated fresh air intake already), so my incremental fresh air into the air plenum (without fan) should theoretically make a net-positive air pressure, wouldn't it?
@@shoebh.3389 sure, if you don't have a dirty air problem, pressurization is not really needed. I an guessing you may have tye hvac system in basement?
Ive spent half the day to find something so simple that you explained, I want to add this kind of thing direct to the furnace which i think will also clean the circulating air with clean air as my wife is a smoker, now I know its not exactly a verner hvr or hvak whatever you call them , they are difficult to install retrofit in my older home but your simple system could somehow be tweaked to accomplish this , so at least Im more informed on how to do this thanks again good job
Nice job explaining the problem and recommending a solution!
Fart fan 😆 fellow Michigander here from Clinton Twp down the road! Building my own house here and this video helps! Thanks!
Should've mentioned to keep an eye on that intake, didn't think of it after I bought my house in the spring, now I checked it and it was half plugged up, been trying to find a video on how to adjust the weighted part correctly and how to know it was done right? Thank you for your videos. (MN)
Move the weight until the baffle stays open. Then slide the weight a little at a time until it just shuts off the baffle. Just a touch heaver than zero gravity.
Found water heater back drafting when a.c. is running. No exhausts fans running. Problem seems to be leaking duct work in crawl space on the supply side. Causing house to be in a negative pressure.
Interesting and dangerous. One malfunction causing another. I never thought of supply air leaking out of a house.
I have a closed combustion (high efficiency) furnace and a atmospheric (top vent) hot water tank in the same room. I have experienced backdraft at the hot water tank vent when running dryer/range hood. I want to move the existing make-up air duct in the furnace room (in a bucket) to the air intake of the furnace to better support the other house equipment (dryer, range hood, etc.) and open a air register in the furnace room to support the hot water tank. I run my furnace fan 24/7. Will this work?
If the furnace is closed combustion it should have 2 pipes to the outside. One for combustion to go out and one for intake air to supply the furnace. It should not be using any house air. The hot water tank only pipes exhaust out but uses house air for combustion, creating negative air. Your makeup air supplies the hot water tank, not the furnace, which maybe isn’t piped for incoming air.
Your makeup air in a bucket also supplies air to the dryer. A big user of house air.
All that being said you need a mechanical contractor to answer this issue in person.
thank you very helpful!!
Thanks
But if you are getting this fresh air from outside which is cold air, doesn't that mean you can now have this cold air not getting warm enough when passing through the furnace?
It will get heated if the furnace is running, I do get an occasional chill but not for long. It is more important to prevent negative air from entering through cracks and voids.
Which one do you recommend for a typical installation? The butterfly damper or the bypass/barometric damper?
I’ll use either, they both are great to have in use.
He's right folks
Will an ERV tied into the cold air return serve the same purpose?
I think it is a higher tech version of what I’m doing low tech. Because it brings in fresh air and exchanges the heat or cool that’s in the house to the air coming in. I believe it will allow more air to come in then what’s going out because it’s not positive displacement. The main purpose of my video is to let the house that has negative air caused by dryers and exhaust fans to be brought in the house in a controlled manner instead of through cracks in windows and doors.
Where is the best place to put on the plenum? At the end, middle or close to the filter?
Low, close to the floor to draw in the coldest air
Hello. Thank for the tips. Do you recommend the method to connect duct to return air plenum or run a duct down into the furnace room into the 5 gallon bucket? Or both methods ?
I actually have both, a combustion air feed into my dryer (because my furnace and hot water tank are both closed combustion) and a second makup air to the cold air return on the furnace, which supplies kitchen and bathroom exhaust fans.
Thank you so much!! I am excited to get the fresh air duct installed and see the results Can’t wait.
Hello again. I am adding a combustion air duct and I’m wondering if the inlet location on the exterior of my home can be 7ft away from a dryer exhaust vent
Do you put those dampers near the exterior wall or by the return trunk?
They mount on an exterior wall, a source of fresh air, and ‘pipe’ to the mechanical room and the furnace cold air return.
sorry, I do not want the MAKE UP air supply attached to the cold air RETURN DUCT.
I want it into the ROOM where the furnace and clothes dryer are/is located. (water heater also)
Why you ask? Combustion air as well as fan blown air.
SOLUTION, Open a BASEMENT WINDOW. works well all winter
comment please.
My editor, who is a little rough at times, removed the part where I show a duct of outside air coming down into a bucket, which acts as an air trap, which is in the mechanical room, supplying the dryer, and the furnace and the hot water tank, which is more controlled than letting free airflow through an open window.
0:55 thanks
So easy to do, so hard to get someone to do it.
Absolutely the wrong thing to do is run that to the cold air return. That needs to go to a sealed box around the burners. Sending to the cold air return is just going to make that air colder and take more to heat it up. I can't believe someone would do that.
Debatable.. just think for a sec ..that duct is in place for on demand VOLUME of air being requested by the fan immediately..what u talking about is supplying oxygen to have efficient burn..but that isnt eating up Volume of air and definitely not vacuuming it suddenly ..the biggest VOLUME of air being displaced and suddenly which creates imbalance in pressure and if air isnt available immediately to supply and balance the extra amount needing at that moment what happens?...its vacuum, negative pressure..so water heater open flue pipe is the easiest target rather than your fresh air in a box.. everything else doesnt move that volume of air in the house in an instant..furnace designed for example 1700sqft of volume to handle oppose to 5 lil burn chambers,or a 3sqft dryer slow and steadt gojng pumping out maybe a 100th of fraction of air and steady..etc.. air has resistance in volume plus duct plus return grilles ..just think why airplanes go so high?..not because they cool,or they just smoked one..less resistance.. to add more sensible reasoning to your noise..god bless everyone
@@MrEuroWolfie The reason to use outside make up air is to plumb it to the burner so when it is burning it isn't pulling a vacuum on the house and then cold outside air is sucked in through doors, windows, and cracks which then must be heated. The burner will also have a good supply of oxygen rich cold air for a better hotter burn. The greatest majority of houses have no setup like they put in and there is no issue with sucking down the flue pipe. The fan kicks in and pulls air from the cold air return and will push it through the ducts to the registers. It's a closed system more or less. The only time air would come down the flu is when a large volume of air is being sucked out of the house by a exhaust fan.
Just OPEN A WINDOW in the room/basement where clothes dryer, furnace and water heater are located.
PROBLEM SOLVED. makeup air for COMBUSTION and fan driven air.
comment please
@@tedlahm5740 And make the entire area cold and the house harder to heat.
My professionally installed he furnace has a fresh air intake built into the return duct supply. Gets filtered and heated just like the return air.