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Community and Q&A

Detached garage ventilation?

ars777 | Posted in GBA Pro Help on

I have a detached garage in climate zone 4A — 3200 ft. elevation just outside of Asheville, NC

The garage is insulated / drywalled and has a very nice finished room above (hardwood floors, beadboard walls). Both rooms are insulated, but neither is conditioned.

The garage has windows on 3 sides and the finished room has windows on 2 sides.

I had always left the garage windows opened year round and finished room windows closed year round (unless occupied).

I have been told that I should keep the garage windows closed, particularly in the summer.

My thinking was that ventilation, even if the air outside is humid, was beneficial to the garage space. For whatever reason, I never considered leaving the windows open to the nicer room above. Perhaps that is a sign.

My question is: should the garage windows be opened in the winter? summer? neither? both?

Do I ultimately need to simply monitor humidity and consider conditioning / dehumidifying the spaces if necessary?

Knock on wood, we haven’t had noticeable issues yet, but I did think I should ask as the summers can be quite humid (although often sunny / breezy as well). Opened windows in the garage below and closed in the room above has seemed to work OK, but is it better to keep closed up?

Thank you.

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  1. ars777 | | #1

    I should also mention that we are not at this home year round, so opening / closing the windows based on conditions is not viable. They will need to be either opened or closed. Thank you.

  2. GBA Editor
    Martin Holladay | | #2

    It doesn't sound as if you have any problems. Either way will work.

    If you aren't seeing mold or condensation problems, why worry? It's your garage -- you can leave the windows in any position that you prefer.

  3. Chaubenee | | #3

    Is the building even insulated?

  4. ars777 | | #4

    Thanks Martin and Joe.

    Yes the garage and room above are insulated, but not conditioned. The room above has furniture, etc. so I keep the windows closed. Garage, I thought best to air out and figured the humidity / potential bit of rain getting in once in awhile might be balanced by the air flow of having windows partially open on 3 sides.

    Agree with Martin that we don't seem to be having issues, but wasn't sure if leaving windows open year round in that zone was asking for future problems....

    I wasn't sure how this differed from the vented / unvented crawl space conundrum other than we have no mechanicals running through the garage. Our crawl is encapsulated and sealed, not vented, and has a dehumidifier. I wasn't sure what, if any, approach to take with the garage and finished room above given that they are not conditioned and I don't see a need to condition them.

    Thank you.

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