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Community and Q&A

Venting conditioned crawlspace air

spudkensington | Posted in Energy Efficiency and Durability on

Would it be advantageous to vent my conditioned crawlspace (50 cfm) to my below grade garage? Since the garage leaks air through the door gaps, would this be a good way to keep the garage dryer/more conditioned than otherwise? Is this a code violation? 


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  1. spudkensington | | #1

    Bump for any input please. Thanks!

  2. Expert Member
    BILL WICHERS | | #2

    Conditioned crawlspaces are supposed to be part of the building envelope, which means the interior air space of the house -- the living areas, basically. If you connect it with your garage, you're linking the garage air space with the interior air space in the home which is a no-no. You don't want any possibility for exhaust fumes, or anything else in the garage that might be dangerous, getting inside where the people are.

    I'd say NO, don't link your crawl space and garage.


  3. spudkensington | | #3


    Thanks for replying. I think I wasn't clear enough. I'm installing an always on bathroom exhaust fan (50 cfm) to vent my conditioned crawlspace as per code. My thought was why waste the air I'm conditioning to the outside when I could have it partially condition my garage. Is this just wishful thinking?


  4. Jon_R | | #4

    I'd install a back-draft damper to prevent reverse flow even if the fan fails. Garage humidity will be high. No idea what code says.

  5. Expert Member
    Peter Engle | | #5

    When the fan turns off, burns out, or otherwise doesn't do its job, then garage air can enter the crawl space through the opening. Code generally prevents any connection between the garage and the crawl space. If nothing else, you would need to have a self-activating fire damper that closes tight in case of a garage fire. It's a good thought, but ultimately probably not a great idea.

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