DIY A/C Unit Cage – Part 1


I have a buddy that recently got into rental houses and wanted to figure out a relatively cheap way to secure the outside Air Conditioning Unit. This is not only one of the most expensive parts of the rental house, but is also the easiest to steal during times when it is vacant. Read more to see what we came up with!

The rate of air conditioner theft really depends on what area you or your unit is in and what copper prices are. Often what happens when thieves steal air conditioner units is they steal the inner copper contents and leave the other parts strewn around in a pile though sometimes they steal the whole unit like the video here:

The first step was to measure the unit and come up with some dimensions. I then went to the whiteboard and made some rough drawings. This is a project that can be made many different ways. This is a pretty simple project that can be done with nothing more than a MIG welder and angle grinder.

DIY Air Conditioner Cage

OOOooohhh pretty.
(not really, but you get the idea)

Air conditioner cages are available on the internet and are definitely an option if you can spare the cash or are on a tight timeline. Here are a couple that I found on Amazon:

In our case, there is more time than money so we are going to try to make our own. As with all of my projects the first thing I do is assess my supplies. In this case I had an old bed frame in the basement (good source of angle iron) and some random leftover pieces of square tubing just the right size for this project. Here is the mess after I cut the bed frame apart with my 7″ angle grinder.

DIY Air Conditioner Cage

I then tacked one side together after adding ~2.5″ per side for space around the air conditioner unit.

DIY Air Conditioner Cage

Gertrude was helping…

I got off easy this time because the a/c unit at my personal house was the same exact make and model as the unit this cage is destined for. So, off to the backyard to check fitment.

DIY Air Conditioner Cage

Still helping… Look out Vanna White.

Even though this unit is rectangular, I decided to make the cage square for simplicity. So I started cutting pieces to weld the rest of the frame together with my chop saw.

When setting up 90 degree angles, it is really handy to use welder magnets like this one:

DIY Air Conditioner Cage

They are cheap and hold metal parts together so you can get them welded together. They come in a couple of different sizes and shapes.

DIY Air Conditioner Cage

Two sides built, now it is time to go 3D!

DIY Air Conditioner Cage

More handy welder magnet uses.

DIY Air Conditioner Cage

Frame all tacked together, ready to flip over.

DIY Air Conditioner Cage

Basic a/c cage frame.

With the frame built, it is now time to start adding some actual protection for the unit. I had half of a sheet of #9 expanded steel laying around. This stuff is pretty cheap at ~$55 per 4’x8′ sheet so it shouldn’t break the bank too bad. I threw the sheet up on some 4″x4″ wood blocks, then after marking the cuts with soapstone, cut it using my 7″ angle grinder.

DIY Air Conditioner Cage

DIY Air Conditioner Cage

I then stuck it on the inside of the angle iron and welded it on.

DIY Air Conditioner Cage

Took it out back and threw it over my A/C unit to see if it still fit. Looks like it will work well.

That is where the story ends for now, mostly because I ran out of materials and need to make a steel run. The plan isn’t for this cage to be totally invincible and super strong. The point of this cage is to make the tweaker wannabe thief go steal somebody else’s stuff instead of yours.

It is like the old story where if you are getting chased by a tiger, you don’t have to be the fastest on earth, you just have to be faster than the guy next to you.

A final note, because I was having an awesome afternoon. This picture is what DIY Metal Fabrication is all about. I get to hang out in the garage with Gertrude, great weather, delicious beverages, and tools while making something useful. A man can’t ask for too much more.

DIY Air Conditioner Cage

My happy place…

Stay tuned for part 2 where we will finish up the a/c cage, figure out how to anchor it to the ground, and install it.