Make-Up Air for Clothes Dryers

I have mentioned this way too many times before....in order for the dryer to operate, you are unfortunately removing 'conditioned' air.....especially in living quarters.....some people have no choice....

for instance, its not just the price of running that dryer, but also the fuel needed to heat/cool the exchanged air.....just something you don't normally think about....

this falls the same for heaters and water heaters that use fuel for combustion.....some are power vented, some also are 'sealed combustion', meaning they have two pipes, one to bring outside air in, used for combustion, and then returned to the outside, without touching your conditioned air from the inside...

I combatted this issue with one dryer in the upstairs bathroom, I punched out the port for side venting, and installed a second hose to pull air from the outside, not a totally sealed system......but it doesn't pull as much air from the inside as it used to......

for any laundry rooms that have a window and a door, it is usually best to open the window and leave the room closed while using the dryer....rather than suck all the air out of the whole house....not everyone can do this.....but keep in mind of what is happening while running the dryer...

I have a gas fireplace, which is sealed combustion, using one pipe, or rather a pipe in a pipe, pulling fresh outside air through the outer pipe, and returning burned gases from the inner pipe....

sometimes not always good to have a completely sealed home, where everything is closed too tight, this is where the flapper vents are added to compensate for exchanges of air, or even trying to open a door from a sealed house/room....

people sometimes forget, for instance if there is no basement and the heater/water heater is installed on the main floor, and needs to breathe in order to operate...

think of some of us who have 4 or more dryers hooked up, and the amount of airflow that must be replaced.....this is when I open a window and close that room off while in use....then again, there are days it brings in a lot of fresh air to exchange....some days good, some days not so much...depends on the weather

just some thoughts to keep in the back of your head....

very good thread....


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Post# 806733 1/30/2015 at 12:22 (3,367 days old) by philcobendixduo (San Jose)
Checkrate/Likes I posted the below in response to a member asking about using a commercial dryer in a home setting. There were no more posts after mine, so I'm reposting here in hopes that other members will share how they allow for "make-up air" when running a clothes dryer. How about other "air suckers" in your home like kitchen and bathroom exhaust fans and fireplaces? ORIGINAL POST FOLLOWS BELOW: I have a 1967 California tract home that has a "rare" indoor laundry room. Most California houses of this vintage have the washer and dryer hookups located in the garage. I always wondered why my furnace had an intake (return air) vent located on the outside wall. I actually blocked it off many years ago because when the wind blew, the draft from the INDOOR intake vent located in the family room would really make the room cold - and drafty! It also allowed outdoor smells like wood burning smoke, skunks and car exhaust to be sucked into the furnace and blown throughout the house. I just read in an online forum that many homes have these furnace return air vents allowing outside air to come in to make up for bathroom vent fans, kitchen vent fans, fireplaces and dryers that suck air OUT of the house creating negative pressure. I just had my house fully insulated and a chimney top damper installed so my house is now much more energy efficient AND there are less places for air to leak in. To avoid sucking conditioned air out of the house when I run the dryer, I open the door from the laundry room to the garage a "crack" to allow air to come in from there and I close the door from the laundry room to the house. I think todays modern "energy efficient" homes have an air to air heat exchanger that allows for outside air to come inside without wasting energy and causing drafts. I wonder how many people have never considered that a dryer "sucks" air out of the house (if it's a vented dryer)?

Post# 806738 , Reply# 1 1/30/2015 at 12:47 (3,367 days old) by rp2813 (Sannazay)
Checkrate/Likes For a while we lived in a mid-'50s duplex that had forced-air heat. It drew air in from the crawlspace below. It was a nice feature on hot days when we could run just the fan only. It had an indoor laundry service porch off the kitchen and we never made any connection between the dryer and drafty conditions. The next two homes we lived in also had forced-air, but those systems drew air from inside the house. Neither house was sealed tight, and the furnaces were located in closets open into the attic for their flues and I presume could draw additional air from that source. Laundry in both of those homes was in the garage. Dave's daughter lives here in SJ and like you, has an indoor laundry room. It's situated in a sort of pass-through between the kitchen and a door to the side yard. Her house is well insulated and weather-stripped, and has double pane windows throughout. I'll have to ask if she notices anything when the dryer is running. Our own house is 90 years old, has an indoor laundry room, and plenty of ways for air to be drawn in by dryers and exhaust fans, but even if that wasn't the case, neither appliance compares to a whole-house fan that would create a vacuum without having windows cracked open in every room. With a gas dryer, I'm much more concerned about a completely sealed exhaust duct to make sure any carbon monoxide fumes are vented to the outdoors.

Post# 806740 , Reply# 2 1/30/2015 at 12:58 (3,367 days old) by Yogitunes (New Jersey)
Checkrate/Likes 1 I have mentioned this way too many times before....in order for the dryer to operate, you are unfortunately removing 'conditioned' air.....especially in living quarters.....some people have no choice.... for instance, its not just the price of running that dryer, but also the fuel needed to heat/cool the exchanged air.....just something you don't normally think about.... this falls the same for heaters and water heaters that use fuel for combustion.....some are power vented, some also are 'sealed combustion', meaning they have two pipes, one to bring outside air in, used for combustion, and then returned to the outside, without touching your conditioned air from the inside... I combatted this issue with one dryer in the upstairs bathroom, I punched out the port for side venting, and installed a second hose to pull air from the outside, not a totally sealed system......but it doesn't pull as much air from the inside as it used to...... for any laundry rooms that have a window and a door, it is usually best to open the window and leave the room closed while using the dryer....rather than suck all the air out of the whole house....not everyone can do this.....but keep in mind of what is happening while running the dryer... I have a gas fireplace, which is sealed combustion, using one pipe, or rather a pipe in a pipe, pulling fresh outside air through the outer pipe, and returning burned gases from the inner pipe.... sometimes not always good to have a completely sealed home, where everything is closed too tight, this is where the flapper vents are added to compensate for exchanges of air, or even trying to open a door from a sealed house/room.... people sometimes forget, for instance if there is no basement and the heater/water heater is installed on the main floor, and needs to breathe in order to operate... think of some of us who have 4 or more dryers hooked up, and the amount of airflow that must be replaced.....this is when I open a window and close that room off while in use....then again, there are days it brings in a lot of fresh air to exchange....some days good, some days not so much...depends on the weather just some thoughts to keep in the back of your head.... very good thread....

Post# 806743 , Reply# 3 1/30/2015 at 13:05 (3,367 days old) by mrb627 (Buford, GA)
Checkrate/Likes *SummerTime* In the Summer time, I try to get all my clothes drying completed by 10 o'clock in the morning to avoid taxing the central a/c. It was more important when I was stuck with the a/c that the builder installed (undersized). Now that I have bumped it up a bit with a replacement unit, it isn't noticeable at all... Malcolm

Post# 806824 , Reply# 4 1/31/2015 at 05:45 (3,366 days old) by retro-man (- boston,ma)
Checkrate/Likes In our previous Gold Medallion all electric house, we installed forced hot water baseboard heating. If the furnace and clothes dryer were running all was fine. If we turned the stove exhaust fan on you could feel a draft in the house for make up air. If one of the fireplaces was on, and the dryer was running and you turned the stove exhaust on at the same time, the smoke would come back down the chimney and smoke out the house. Learned real fast to open the slider in the living room a crack to let makeup air into the house.It was immediate where the smoke would reverse direction and go back up the chimney. Being in a newly constructed house we now have an air to air exchanger set up in the heating system to make up air. No drafts here with plenty of air to exchange and make up. That unit uses electricity for the blower system so not even air is free anymore. lol Jon