How To Secure & Burglar Proof A Window AC Unit

You’ve finally gotten your window air conditioner unit installed and cooling your home, but you might be worried about being burgled.

You have spent your hard-earned money to feel more comfortable at home, and you don’t want to see your AC unit suddenly being taken away by a thief. Or worse, someone accessing your home through an unprotected window.

Keep reading to find out how to secure a window AC unit, maintain your window air conditioner safely, and deter potential burglars.

6 Ways To Burglar Proof Your Window AC Unit

You want to mount your AC unit solidly to stay in place, but you likely want to take additional steps to secure the air conditioner in the window.

AC Cage/Window Guard

An AC cage makes it hard for a burglar to pull the unit out of place because it prevents anyone from even getting to the unit itself. Think of the window guard as a fence around the AC.

The cage also acts as an additional safety measure should your window unit become dislodged, catching it before it can fall onto people or property below. You can find quality AC cages at most home improvement stores.

Special Window Lock

Some AC unit installations happen in windows big enough that there’s room to open the window and crawl through it even without moving or removing the air conditioner.

In the face of a rash of this type of burglary, the University of Michigan specifically urged residents to install an AC window lock that prevents the window from opening any wider than the size of the air conditioner unit. Your window manufacturer may have brand-specific locks available, and your local hardware store or locksmith certainly will.

Air Conditioner Support Bracket

Your window AC unit might stick one foot or more out of the window. That kind of weight needs more support than just wedging into place, so you’ll need a window AC support bracket.

More than just a strut stuck under the outer edge of the unit, support brackets mount with bolts or screws to the unit and the structure. Some cities recommend support brackets on all such units, and some—like New York City—require brackets on units installed above a certain height.

Brackets serve two purposes—they keep the unit from falling or damaging your home by pulling away from it, but they also make it that much more difficult to remove the AC from the window.

Install Flaps

Since your window unit air conditioner probably won’t fit perfectly into your window, most manufacturers package their ACs with flaps to fill the space on either side of the unit. Use these, for heaven’s sake.

Most of them are sizable to fit, as they use an accordion-like structure to allow them to expand or contract to fit. At the very least, the flaps serve to keep you from having gaping holes on either side of the AC unit—holes that let cool air out and hot air and bugs in.

Window Alarms

A 20-year British study found that the drop in home break-ins that began in the late 20th century directly correlated to the rise in home security system installations. The findings demonstrate that security systems—alarms—work. They do what they’re supposed to do, keeping burglars out.

Mainly, they work by raising the risk to the potential intruder and is one way how to secure windows with AC units. Installing a window alarm on the window where your AC unit sits serves as another deterrent to thieves.

Home Security Camera

With the rise of the Internet of Things, more people have access to home security cameras in addition to security systems.

Like alarm systems, the visible security camera tells the intruder he’ll be preserved on digital video for all to see, which can be a powerful way to discourage him from trying your windows. If he tries to get into your home anyway, the police will probably get a nice photo of his face and distinctive neck tattoos.

Hundreds of local police departments have partnered with security camera companies to help with crime prevention, which shows that installing one or more of these helpful gadgets can be a genuine asset when it comes to securing your home.

Are Window Air Conditioners A Security Risk?

At first blush, you might think that having a window AC unit waves a flag at burglars—“Look over here! An open window!” because, well, you have to have the window open so the unit has a place to go and the air has a way into your home.

And sure, if you set your AC unit on the window sill and hope for the best, that won’t be the most security-minded thing you’ll ever do. But when it comes to asking are window AC units safe, they are when correctly secured in place.

Besides keeping the units from falling out of the window, another aspect of AC window unit safety relates to keeping burglars from seeing those units as easy access points into your home.

Why Is Window AC Security Important?

Home security experts estimate that as much as 23% of burglars unlawfully enter a home through a window, so it wouldn’t be a fluke for a burglar to parlay a poorly installed unit into a potential payday.

Are Window AC a Security Risk

Pros & Cons of Window AC Security Measures

Taking extra measures for security around your window AC unit seems like a no-brainer. You have to do something to keep it in place, and as mentioned earlier, some municipalities require at least some measures to be taken in this area. But even security can have its plusses and minuses.

What We Like
  • Your window unit won’t fall out of its spot.
  • You’ll be less likely to lose cool air through leaks to the outside, saving you money on cooling costs.
  • Knowing it’s harder for bad guys to get into your house makes living there a little less stressful.
What We Don’t Like
  • If it’s hard for burglars to get at your window AC unit, it will be hard for you, too.
  • When it comes time to remove or replace the unit, it will be harder since you already installed measures to ensure it stays in place.
  • Things cost money. You already spent some on the AC unit, and buying locks, alarms, or flaps will incur additional costs.

Related Article Full Window AC Buying Guide

Pros and Cons of Window AC Security Measures

People Also Ask (FAQ)

And here are some of the frequently asked window AC security questions.

Are window security measures also childproof?

They can be. Securing your windows against burglars makes it more difficult for a child to get them open. Window guards for childproofing serve the same function as window unit security—keep the window in place and the AC from coming out of its spot.

Can my AC fall out of the window?

It absolutely can. Window units can be heavy, and if yours sits precariously perched on your window sill, a bump against it can spell disaster. You absolutely must anchor your window AC unit in place, even if you don’t care about security risks. A falling AC unit will quickly suffer damage and, at worst, can fall on a person, causing serious injury or death.

Can a piece of wood be used as a material for securing a window AC?

Can it? Sure. Should you use it? Probably not. Propping your unit up with a stick is a fool’s errand. Screwing wood panels or boards in place can be more secure, but wood is prone to rot and other damage that metal fasteners are not.

Do I need to screw in my air conditioner?

One hundred percent yes. Go back to the second question in this FAQ—if you don’t screw your window unit in place, you’re just asking for trouble.


So are window AC units safe? They can be. They can bring much-needed relief to your home, and if properly installed and secured, they present little danger to people and property around them. Also important to know is that if they’re not secure, they open your home to the possibility of a break-in, so take the necessary steps to keep your home safe.

Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.