So my apartment has an attached garage and I love having it, but I also live in Las Vegas where, today, it was over 100F outside. I have been considering air conditioning the garage, or even just a corner of it for a workshop with a cool breeze, but I have a little problem - since it's an apartment I can't modify the garage in any way to vent hot air outside.

I've considered portable evaporative coolers, and while I've got one and it works, it only works for a little while - since the garage is so enclosed the evaporative cooler eventually humidifies the air to the point where it stops working. This also creates problems with condensation and since my hobby space in the garage is to be used for electronics, radio and various other electricity-friendly pursuits, condensing water droplets is a very bad thing.

What can I do? Is there any way to lower the temperature of the garage air without somehow venting hot air back to the outside world? Would combining an evaporative cooler and a dehumidifier work? If so, how should I arrange them for optimal cooling?

  • 1
    Without some option to remove the heat, you are pretty much out of luck. Air conditioners work by moving the heat from one place to another... you need a way for either an air duct or refrigerant lines to get the heat to the outside.
    – TomG
    Commented Sep 8, 2012 at 20:14
  • What about getting another door on the side of garage and put the original one back when you move?
    – user36117
    Commented Apr 30, 2015 at 6:01
  • Sounds like you need to open more windows if you're going to use an evaporative cooler. If there aren't enough, open the door.
    – iLikeDirt
    Commented Apr 30, 2015 at 17:12

4 Answers 4


Unless you can insulate, it will cost a ton of money. I get that it's a rental, but maybe the landlord won't mind if you insulate the garage. Having done that, get one of these AC units that only require you to make a 6" hole through the wall:

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Talk to your landlord, they may not mind these slight mods, especially if you pay for the insulation.

However, if you really can't modify anything, another option is to build a smaller insulated shack in the garage, and AC that. Or, build a temporary wall to isolate part of the garage as an insulated and AC'ed space.

  • The single-hose models are very inefficient, they pull in unconditioned air from outside the space to blow out the hose. Barely tolerable inside a house where it's mostly bringing in air from the next room, but would be particularly ineffective in Vegas where it's bringing in 110 degree outside air. Even the dual-hose models are not that great, but would be an improvement over the single-hose model. A window unit A/C would work much better (with a much larger hole (or Window) being required). Consumer Reports said portable units delivered about half their rated cooling capacity in testing.
    – Johnny
    Commented Dec 19, 2014 at 22:01

A evaporative cooler and a dehumidifier together would likely just end up heating the garage. Consider any sort of heat pump however. The pipes can go under garage door, with just a little temporary gasket to keep it sealed.

  • I thought you wrote "under the garage FLOOR" until I read it more closely... :) - but the problem with having the garage door partly open is that there will be a huge gap at the top.
    – dbracey
    Commented Sep 8, 2012 at 16:19
  • use a gasket at the top. you will need to block heat re-entry where you can, otherwise you will just waste money.
    – Rory Alsop
    Commented Sep 9, 2012 at 0:39
  • Not gonna work - door moves away from the wall as soon as it starts to open.
    – dbracey
    Commented Sep 9, 2012 at 14:59

The room-inside-the-garage idea sounds best to me, but here are a couple other crazy ideas.

The basic problem is you need to push heat out of the garage. You either need a thermal barrier to keep it from coming back too fast, or you need to move out a lot of heat faster than it races back in.

The room-inside-the-garage idea solves this by creating a thermal barrier between the room and the rest of the garage and pushing the heat from the room out into the garage.

As an alternative, use the garage as a room inside your residence, and push the heat from the garage to the residence. Run an air conditioning unit and pipe the hot air into your main residence, where that region's AC can handle restoring a more reasonable temperature. You'd want to circulate the air throughout the apartment so that you don't end up with a hot spot right by the exhaust, and you're going to be spending a lot of money fighting against the lack of garage insulation.

You could also consider insulating in such a way that you can remove the insulation when you vacate the apartment. I'm thinking exposed batts of insulation placed against the exterior walls and particularly against the back of the garage door panels. You will doubtless need some sort of bracing to keep them up against the wall. There might be a better product for this sort of removable insulation that I don't know about, as well.

Along the same lines, you might be able to get away with venting a portable AC unit outside through a small hole or holes in the wall. Patch those holes when you leave. Or maybe there's a window in the garage that you can open, fit with a wood piece the same size as the bottom half of the now open window to plug the hole, and then cut a hole in that wood piece to run the exhaust pipe to the outside.

  • 1
    I highly recommend that you do not move air from a garage into a house or apartment. Car exhaust is pretty nasty. Even if you minimize it, it's not worth the risk in my opinion.
    – Danation
    Commented Jul 21, 2014 at 18:55

I know that this thread was a long time ago, but here is a possible solution for other people. If your garage door is the typical multi-hinged garage door that "rolls" up into the area above the garage space, you can replace one of the panels and make a hole in it to accept the exhaust tube. Disconnect the tube to go in and out of the garage and fashion some sort of plug for the hole while the tube is disconnected. I would also create some sort of screen to go over the end of the tube while in use to keep bugs out of the machinery. Then, when you are ready to vacate your apartment, replace the original garage door panel and take the one with a hole with you, along with your AC.

I own my home and plan to put a pet door into the lowest garage door panel. I will then make a panel to fit in the pet door and make my hole in that panel to accommodate the AC tube. If we ever sell the house, we will just have a garage door with a pet door in it, or we can replace the door panel at that time.

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