So, here's the dilemma. I want to install a window unit in my garage. I know how to do this, but my wife isn't supportive of the idea because we are trying to sell the house currently. Anyways, rather than fighting this never-ending battle with her, I'm trying to see if I can somehow still use my window unit without actually cutting a hole in the wall, etc.

An idea that I had was to figure out somehow how to route the exhaust to outside. This is obviously an issue because I would need an opening somewhere in my garage.

Is it possible to use my window A/C unit in my garage without actually installing it in the wall?

  • You could temporarily wall off part or all of the garage entrance, and install the AC in the temporary wall.
    – mbeckish
    Commented Jan 4, 2016 at 18:41

3 Answers 3


You may be able to rig up something whether the compressor-side air intake and exhaust are piped outside, but the efficiency will be low and you may risk burning out the compressor by working it too hard.

If you want something you can install in a small opening, you might consider wheeled portable AC units which come with a flexible duct.

If you're still determined to try it, note that window AC units have two sets of air intake & exhaust:

  • the "inside" side that takes air from inside (usually through a large filter on the front), cools it, and blows it back inside
  • the "outside" side that takes air from outside, heats it (with the heat removed from the cool side) and blows it out the back.

On a typical window AC unit the "outside" air comes in through vents on the side and top of the unit and is blown out the coils at the back. So you will need to make sure both of those parts are getting the airflow they need. And they can't be the same duct, or else you will just get super hot air recirculating through the unit.

  • How much airflow is needed on the outside? I've got a window well that has a cover. It's not airtight, but would this have to be open? Commented Jul 3, 2014 at 23:33

You can place the whole unit outside make it water prof. Duct the (inside) which is the inflow side and the cool air to the inside of your garage.


If you have an attic access in your garage you should be able to vent it to the attic. If the AC unit is expendable, try running it face down. If it tolerates that, you could set it in the attic, on boards facing down that hatch (until it falls on a buyer/inspector and gets you sued).

If you could rig two ducts through your attic access, but that's going to look much worse.

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