Window air conditioner security locks, bars, and tips.

Window AC Security – Air Conditioner Lock, Bars, Tips

Window Air Conditioner Security

How to secure a window AC unit…

Window AC security is important. When the weather warms up, it’s time to install your window air conditioners. But this could also expose a security risk too. A burglar could get into your home through a window after pushing in the air conditioner on the 1st-floor. Or the burglar might steal the AC unit!

Here’s what you can do about securing your window AC unit. I’m going to list a number of tips and product suggestions. The things you can do to help with window air conditioner security.

  • Window AC Security and Stability Pack (AC unit support rail bracket secures with window sash)
  • Window Locks (sliding, vinyl, metal)
  • Window Stopper Wedge
  • Window Lock Bars

Read on for several up-to-date suggestions!

Screw the Window AC unit Top Support Rail into the Sash

This works for wood windows (see below for vinyl or metal), and other options.

Most window air conditioners are installed and simply held in place by gravity. It’s tucked behind the window sash which keeps it from falling out. Maybe there’s a small screw holding the top, and one or two on each end of the accordion side-panels.

Some people don’t even install a single support screw into the AC unit top support rail. Since the window air conditioner is held in place by gravity and its downward force against the window sash, that’s good enough, right? No, not so much..

So, what can you do to better secure your window air conditioner AC unit?

At least install a screw through the air-conditioner’s top mounting rail into the window sash. Most window air conditioners include a pre-drilled hole in the top center to accommodate this.

Consider drilling additional holes through the AC’s top support rail to accommodate more screws into the lower window sash (see illustration below).


UPDATE: If you cannot, or prefer not to screw into the window, there are several alternate ways to secure the air conditioner unit, some of which I’ve listed below. One method is this clever little bracket that will keep the AC unit from being pushed out:

Stabilizer Pack

To install the security bracket, the AC was positioned properly in the window and the small u-shaped end of the bracket was placed over the upper flange (rail support bar) of the air conditioner.

The window was then closed over the large u-shaped end of the bracket.

Thin weather stripping was placed between the window sash and the upper flange of the air conditioner to seal the small gap (due to the thickness of the bracket).

The bracket was secured to the flange of the air conditioner by tightening the provided bolt through the bottom hole. The bolt wasn’t overly tightened since it essentially prevents the bracket from sliding too much forward and back.

(I didn’t use the bolt in the top hole since the air conditioner flange was too high.)

Although the bracket looks to be a bit loose, it can’t be removed and the air conditioner can’t be pushed out of the window unless the bottom sash is raised.

The provided window locks didn’t work for my windows, so I used the Windobully Window Lock to prevent the sashes from being raised or lowered.

~ from a product review

Install Security Window Lock for your Portable Air Conditioner

A convenient window lock for air conditioner security: (Sliding Window Lock, Window Stop, Window Restrict)

A window lock will prevent or deter the burglar from pushing and forcing up the window.

The AC unit may be screwed to the sash, but if the window itself isn’t locked it’s still possible to force open and reach in and shove the air conditioner. Install window frame locks to prevent this.

AC Window Lock – Vinyl & Aluminum

For Vinyl Windows – you might consider this popular window lock as shown below:

>> Defender Security Sliding Window Lock for Vinyl Windows
(view on amzn)

>> Defender Security Sliding Window Lock, Aluminum

Sliding window lock for vinyl windows

Window Security Wedge

Another clever idea is a window wedge. Here’s one from a ‘Made in the USA’ company…

Bonus: This also works on many double hung windows. What I mean is.. windows where the upper window can also slide down. Because there’s Velcro attached to the upper window (for attaching the wedge in a chosen position), both the upper and lower window panes are essentially locked in place. You can see the Velcro in the picture below if you look closely.

Note that you need an approximate 1/8″ gap or recess to work with (upper pane sash frame recessed from the lower pane sash frame) – so the window won’t rub or get hung up on the Velcro under normal up/down operation. Check your window first.

>> Window Stopper
(view on amzn)

Window Lock Wedge

Window Air Conditioner Security Bars

An adjustable window security bar. It’s designed to fit between the top/inside window frame and the upper sash (which is partially open due to the window AC unit). Perfect for when a portable AC unit is installed.

The window security bar fits into the gap (example shown below). Measure the gap with the AC unit installed to determine which security bar will fit, even though they’re adjustable.

>> Sturdy Steel, Extends from 10″ to 17 1/2″
(Jacent storefront on amzn)

>> Sturdy Steel, Extends from 15 1/2″ to 29 1/2″

‘Do It Yourself’ Window Security Bar:

While the air conditioner is mounted in the window, measure the distance from the upper window sash to the very top of the double-hung frame itself (with AC installed). Cut a wooden dowel to snugly fit – which can be wedged to prohibit the window from opening further…

Window Air Conditioner Bracket

It’s also a good idea to get a window air conditioner bracket. It makes it harder for the burglar to get the air conditioner out from the outside. You could also secure the portable AC unit to the bracket in various ways.

>> Brackets on amzn

Window Air Conditioner Security Tips

Ultimately, you are not going to stop a determined burglar. But you will probably stop the majority of amateur burglars who are looking for quick and easy entry.

Consider removing any 1st-floor window air-conditioners when going on an extended vacation. A few minutes effort may be worth it…

If a burglar happens to pick your home because they see a window air-conditioner hanging out of a 1st-floor window, when given a hard push and it doesn’t budge, they will probably move on.

If the burglar pulls or pushes on the air conditioner while attempting to lift the window sash, it will not readily come if you’ve taken the precautions mentioned above.

For additional protection, consider window alarms and/or a house alarm system.

Vibration Sensor / Glass-Break Window Alarms

You could also plant thorny bushes… rose bushes, blackberry bushes etc. just below your windows for deterrence…

A wire cage or bars to cover the outside of the AC unit without restricting its operation. Though I have not personally found a ready-made product for this. It would involve securing directly into the home’s siding, and would obviously be unsightly to an extent.

My Preferred Brand of Window AC Unit

Window air conditioners don’t last forever. I’ve gone through a number of randomly purchased brands over the years. Lately, having done some research and checking reviews, I determined that the Midea brand was best for me. I now have two of their 10,000 BTU units and a 5,000 BTU window AC unit. They’ve been excellent. (just my 2 cents)

You could even have one shipped right to your door:

>> 6000 BTU (and other options)
(Midea on amzn)

More security-related articles:

3 Ways A Burglar Breaks In, 80 Percent Of The Time

7 Mistakes That Burglars Love You To Make…

10 Tips For Better Home Security


    1. Ken, We bought an 8000 B.T.U. window AC by Midea. It is U shaped, so it has less noise associated with it. My son and husband stuck in in the master bedroom window last year and we ran it off our solar, set up with just twelve panels, into our generator. On low, it kept the room very comfortable. We then opened other doors, so it could cool the canning goods in the mud room and take the humidity out of the great room. We closed doors to the den and another bedroom. There is a stairway going to a bed/bath upstairs, that we couldn’t do anything about, but close the door, so that is a drawback. In a grid down situation, we would have to hang plastic sheeting over that tall doorway. This unit, being a new idea, was very popular and hard to get. The first one we ordered came damaged, so we had to haul it back, but we love this one. Once we tried it in Aug. we packed it up again.
      B.T.W. When I said I didn’t do links, I didn’t mean I do not use them. This summer, I ordered a larger American pressure cooker, and big Berkey through your Amazon link, along with other items. Life straws were on sale yesterday as well.

  1. Been there done that : )

    My window was a slider v up/down. I did lock myself out, couldn’t find the spare key that was in the bush and so thought that I could get in without doing any damage. Wrong.

    The ac unit hit the floor before I could react. Put a pretty good dent in it but didn’t damage the window. After that, seeing how easy it was I did a better job of bolting it down.

  2. I found a latch that you can attach to the top window that has a wedge shaped cover that can be opened flat to open the window the full way. With the cover in place, it limits the travel of the upper & lower windows to whatever height you install it at (I did 4″).

    I know Anderson has an expensive version of the same thing on Amazon, Anderson Double Hung Opening Control Kit, but the inexpensive version at WallyWorld had done the job find for me.

    Hope this makes sense, will try to find a link…..

  3. Unfortunately, we have those casement windows that crank out sideways. I wouldn’t mind having just one or two window units so we wouldn’t have to run the whole house AC. I did find out there are small stand alone units for individual rooms. Might try one of those. And they are on wheels, so you can move them from room to room. They look like a tall room air purifier.

    1. DJ5280,

      I have one of those stand alone units for the few times it gets unbearably hot here. It definitely helps. One thing to be aware of that you might have to find a work around for. These are portable in the sense that you can roll them anywhere, but, they must be vented to the outside when in use. The venting set-up is geared for double hung windows – adjustable sliding sides with a hole for the vent tube to attach to. I don’t see how that would work with a casement window. If you knew where you wanted it, and were handy in the carpentry area, you could always create your own venting to outside.

      1. I had purchased two of those roll-around AC units several years ago when we were renting an A-frame home during an interim 2 year period prior to landing at our current AO. Regular portable window AC wouldn’t fit the crank-out casement windows. Regarding the venting for the roll-around units, I had to build it (plywood) to fit a given window. It wasn’t terribly difficult, but it was the only way for it to install and function properly.

  4. Believe it or not, thieves will even steal a big Central Air unit for the copper it contains. I recall living in Orlando Fl. about 15 years ago and the City planted a bunch of new trees along the I-4 interstate. Later that week (2 am) they caught a gang digging them up to resell. Yes, window units say, ” Please steal me!, or break in for even better stuff”.

    1. My point is, folks will steal anything. Example: DW sold medical equipment (Pulse Oyx’s) in south Florida. The medical students/ future Doctors used to steal $3,000 pieces of equipment from the Operating rooms at night so they didn’t have to buy them when they opened their own practices.

  5. S.W.

    One of the nice things about the portable inside units is the only thing possibly visible from outside is the vent opening – nothing sticks out. For less visibility, one could vent from a window/side of the house that is more hidden from public view.

  6. Gee, didn’t even know that about the venting issue. Thanks all. Guess we’ll stick with the central air. Good thing it’s been a cool spring and haven’t needed it yet. Got enough on my plate right now…..

  7. I had brand new vertical double sliding windows installed. Each side can slide open. When putting in my portable a/c vent, there is no way to lock both windows. If I put a lock on the inside window the other outer window can still be slid open. Wish I knew that before spending thousands on new windows.

  8. Seattle Rain,
    If the windows are running in a slide there is fix. You could put a stick in the track of the outside window, from the inside to keep it from opening more. Then Lock the inner window.
    If worse comes to worse, you can always drill a 1/8″ hole through the track into either one or both windows and put a small screw in there to lock them “in their tracks”, or a screw in the bottom of the track that sticks up to stop the window. If you are worried how well these will hold up, well…. if anyone is really desperate they will just break the window and have off with your AC unit, or climb in. Just take some time to look at it, you’ll find a way to lock both in place. Good luck.

    1. Minerjim,
      yes sir, unfortunately windows are the weak point in any home security system. three locks on every door and they can still get past it with a rock or crowbar through a window. ya can’t stop them. all we can do is slow them down. especially in the boonies. where i live people could back a u-haul up to the front door, load everything and no one would see them.

  9. We have roses planted under our windows. It’s not impenetrable but it will be very uncomfortable and thieves will bleed before they can get in.

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