So, I have an unheated garage, but it is insulated. It maintains above freezing due to the contact with the house, but it still gets intolerably cold. I've considered routing my electric dryer out there to help keep it a bit warmer. It's not intentional heating, and would only coincide with the dryer, but I'd think that dumping some hot air into the garage would raise the temperature a bit.

Are there any major concerns with doing this? I'm still planning on getting a space heater out there for when I'm actually out there, but I'm thinking that it would be a slightly more productive use of the spent heat in my dryer than just dumping it out the side of my house.

3 Answers 3


Dryer air is hot, but more importantly, it is very moist. The high humidity might not be a huge issue when it's cold outside, but when it warms up, it could lead to mold or other moisture related issues. Also, even though your dryer does attempt to catch lint on its internal lint screen, some dust is present in the exhaust air which will eventually cause a mess in the garage.

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    Could promote rust too.... If I wanted to do this, I'd consider running the dryer vent through a dust separator to catch most of the lint, then an extended length of duct for heat transfer, then dumping the humid air outside.There would be som condensation in the duct, but hopefully that would be picked you again and carried outside later in the cycle. (Yes, I too have wanted to rescue that energy...)
    – keshlam
    Jan 19, 2016 at 15:35
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    Good point - kind of a DIY heat exchanger...
    – JPhi1618
    Jan 19, 2016 at 15:37
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    @keshlam If the duct is too long, the blower could be overwhelmed. This could lead to poor performance, and premature failure.
    – Tester101
    Jan 19, 2016 at 16:33
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    @Tester101: True. Going up a size in ducting would help alleviate that... I know someone who exhausts their drier thru a filter into their basement, and then runs a dehumidifier to suck all the moisture back out. Probably not efficient but it's a case where proper ducting would be awkwarc.
    – keshlam
    Jan 19, 2016 at 21:20

Check your local building/fire codes. Here in Ontario, Canada, blocking any possible flow of carbon monoxide from an attached garage to the house proper is a major concern. Taped drywall joints, taping of any electrical boxes, sealing of any penetrations, self-closing passage doors to the house are all mandated. A 3 or 4 inch duct leading directly to the laundry room would simply not fly...

  • It is an electric dryer, therefore no carbon monoxide.
    – gbronner
    Jan 19, 2016 at 23:17
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    Uhh... Garage... car in garage... CO in house... people don't wake up...
    – DJohnM
    Jan 20, 2016 at 1:01
  • The vent is only open when the dryer is running, and modern cars produce little to no CO.
    – gbronner
    Jan 20, 2016 at 1:56
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    @gbronner You're using reason, which is no match for a building code. Jan 20, 2016 at 3:14

You can use a Dryer Heat Diverter: dryer heat diverter I've used one for 30 years; in the summer you vent the dryer to the outside, and in the winter you vent it to the space to be heated. For a large garage, the extra humidity in winter won't make a difference.

You get about 10k BTUs per run.

  • This looks like something I could use; I live in New England, and we have to run the basement heater zone in the winter to ensure pipes don't freeze... recapturing even a little of that dryer heat could stand to help me save on heating costs.
    – Doktor J
    Jun 30, 2017 at 14:14

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