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Garage ventilation requirements/calculations?

E47mJdAip6 | Posted in Building Code Questions on

Working on an energy retrofit project and the client is wanting mechanical garage ventilation. I’m having a hard time finding information about how to figure out how much he needs. Is it just a matter of how much he wants? Some other discussions online seem to be about commercial garage areas, but others seem to have calculations for residential ones. Some direction for where to search, or some answers outright, would be most helpful.

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  1. E47mJdAip6 | | #1

    Forgot to mention climate. Durham, NC. Mixed humid.

  2. GBA Editor
    Martin Holladay | | #2

    I'm using common sense here, but I think a 100-cfm bath exhaust fan on a timer should work fine. For more information, see How to Keep Garage Fumes Out of the House.

  3. E47mJdAip6 | | #3

    Hi, Martin.

    Yeah, I've tried to use some common sense on this one, too, though the client really wants to move a lot of air in this big garage. I was trying to find out if there are any requirements, or if there are any code related protocol I can refer to so he can compare his preference to a baseline. 36x24x10 garage. From your response, it seems just giving him what he wants is in order (well, it almost always is). I'll check your link. Lisa dropped me a line on email, too, her primary concern being how well the house/garage common wall is sealed to ensure that the fans are not pulling condition air from the house. A passive inlet should address that, eh?

  4. E47mJdAip6 | | #4

    Recommended passive air inlets that seal well when not being used?

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