I've seen many posts about how you can't install a window AC unit through the wall. However, I have the opposite question. Can you install a through-the-wall AC unit in a window? It seems like someone would have created the hardware to do so, but I can't find it.

Specifically, window AC units have a bracket on them that secure them when the window closes on them. Essentially, I would be looking for a sleeve like you have in the wall, but with the appropriate hardware to mount in a window.

I know it's not as efficient as a window AC unit, but we moved into an apartment without a wall sleeve, so we would rather not buy another unit.

4 Answers 4


Wow and here after all these years I thought they were the same thing.

Well they are the same, basically. The part that is critical is the external vents can not be blocked by the wall, and that’s where the problem comes in - because of the thickness of the wall. However, going from a wall mount to a window should be no problem at all, other than the mount and making sure to tilt it just enough that the condensate drains outside.

I state this with the understanding that the unit has the normal fully enclosed system except the coils and air vents (I have not seen one that was not enclosed, but wanted to cover all the bases).


It seems to me that it could be supported from the window frame by adding rails (red) across the top and the bottom of the sleeve (blue) that catch on the window frame (green).

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side view outdoors on left indoors on right.

I'd go with 1" aluminium angle for the rails and attach them to the sleeve with stainless gutter bolts with locking nuts. I'd have a fiber washer under the bolt heads of the lower ones to prevent leaks.


Follow the advice from @Ed Beal and remember to make sure that none of the louvered spots are being obstructed. There is no difference between a window mount or a "through the wall" installation except that the wall installation is a permanent opening.


Through the Wall units work perfectly in the Window , just put L brackets on top of the unit where a Bar would normally attaché on a window unit and you can just slide it to one side and take the front off and screw it to the window in multiple spots if desired and then fill in the rest of the window with something or get the peel & stick side panels from Walmart. You can usually pick up a TTW unit on Facebook Marketplace cheaper than a window unit , I know because I sell them at a Heavy Discount and Brand New ! North Alabama here !

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