I have this air conditioner that is designed to be used with vertical sliding windows. The problem is that I have a horizontal sliding window. I understand that the air conditioner I have is designed to be held in place by the window sash holding the top of the unit. I have seen solutions such as this answer where a support frame is installed in lieu of the sash to hold the air conditioner in place. I am very inexperienced with carpentry so I was hoping there is another way to do this for my first project. My HOA requires that I install a air conditioner support bracket under the air conditioner. My question is: Can I install my air conditioner using ONLY the support bracket to hold it in place and keep it from falling?

The answer to this question seems to indicate that I can use only the support bracket to keep it in place. But it only has one up-vote and is not accepted so I wanted to make sure and get more concrete answers.

One of my concerns is that the support bracket that I bought seems to be too narrow compared to the air conditioner. The bracket is 5 inches wide and the air conditioner is 19 inches wide. It seems like the air conditioner could just tip over one side or the other. Also, the product summary for the bracket says that it transfers weight from the window sash for safety. But I'm not sure if that means that it works without a sash, or that it is supposed to complement the sash.

Here is the support bracket:

Support Bracket

Here is the air conditioner:

Air Conditioner

  • What do you plan on putting above the air conditioner, since your window slides left-to-right? Aug 2, 2016 at 3:06
  • @RobertNubel If you mean to cover the opening, I cut out a piece of plexiglass to fill it. Aug 2, 2016 at 3:11
  • That bracket supports up to 160 lbs. But from the top critical review on amazon: "To keep the lower bracket from slipping down, I had to drill a hole in the lower pad and drive a screw in the wall. To get the AC unit to sit flat on the bracket, I had to cut a piece of the right thickness wood and insert it between the AC and bracket. By the time I got done messing with this thing, I might as well have built my own wooden bracket and saved my money." Aug 3, 2016 at 21:16

3 Answers 3


NO. the bracket is designed to complement the strength and stability of the upper sash. You must cut a length of lumber to span the opening and stabilize the unit at the top, like the upper sash on a hung window would. Thin Plexiglass alone is not strong enough either.


The bracket is entirely sufficient to support your AC. That's doesn't mean that in some freak occurrence it couldn't come out of the window. If you want to add to the margin of safety, you want to prevent the upper sash from loosening enough to prevent it from rotating out. Most units have screw holes in the frame of the AC that allow you to fasten it to the upper sash. Otherwise a small screw or nail to prevent the sash from moving will do the trick. At that point not much short of a tornado is going to get it out of the window...

Hope this helps!

  • Sorry, I probably didn't make my post clear enough. I have a window that slides from left to right so there is no upper sash to attach it to. That is why I'm asking if the bracket can support it by itself. Aug 2, 2016 at 2:50
  • Gotcha... well, the principals are the same really. If you're concerned (and I wouldn't be) assure that your window cannot open. If you can't/don't want to drill a hole or use a screw, just cut a length of dowel or broom handle to pin the frame in place, much as I'm sure you've seen people do with patio sliders.
    – PaulBinCT2
    Aug 2, 2016 at 3:20
  • +1 for noting that the bracket is self sufficient, but -1 for not knowing that the bracket is purposed for windows without upper sashes; and +1 for saying to make sure the AC doesn't wobble. And as a side note (@Andrew): make sure the AC is not leaning forward (into the house) or else condensation could drip inside the house. Aug 3, 2016 at 21:08
  • @BenWelborn ... is the scoring directed at me? Mea culpa, I should have noticed the horizontal window. Although really the issue is the same for the most part. I assume(d) hopefully accurately that the window frame height is sufficient to give the AC bearing at the top. If not, certainly the OP (who sounds like a smart enough guy) should arrange for some adequately strong top member. All that is a long way of saying... as I get settled in here, I'll learn to read all the fine print ;)
    – PaulBinCT2
    Aug 3, 2016 at 21:34
  • @BenWelborn I'm confused by the +1 and -1. If the bracket is self-sufficient (as I think you are saying), then does it matter that this bracket will be used for a window without a sash? Also, what do you make of Jimmy Fix-it's answer? I think I will end up using a 2x2 length of lumber to span the window opening to keep the AC in place. Aug 3, 2016 at 21:45

A simpler solution would be to install a "no drilling and no tools required window A/C bracket". For instance, the TopShelf A/C Bracket installs in minutes from the inside and is adjustable to myriad window sizes and you won't have to drill into the window frame leaving permanent damage to the window frame.

  • Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably take our tour so you'll know how best to contribute here. Jan 28, 2020 at 14:48

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