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Installing Air Conditioning in your garage.


So I know my friends from colder climes think I'm nuts when I complain about the summer heat. But the reality is that unless you've spent a summer in Phoenix you just don't know what hot really is. From mid-May to the end of September the average temperature in my garage ranges from 90 degrees in the morning to 115 in the afternoon, and can be even hotter on really hot days. While our winters are nice, the summers are just plain misery out in the garage. I opted to finally do something about this: install an air conditioner.

Also, if you live in a colder area, many of the newer windows units have heat pumps in them. So, you can use it to heat your garage in the winter if need be.

Now, my garage is actually a converted car port. When the walled in the garage the original owners didn't put in any sort of windows. So, instead I've a blank wall to look at. Even though the unit we're installing is a window unit, it's not necessarily going to be simple because there's no window to install it into. I did note, however, that this patch of wall looks like it should be easy to disassemble and I think there's a stud running down the center.

The builders used thin sheet boarding for the wall instead of sheetrock, which for disassembly purposes makes life a lot easier. There were two panels that made up this section of wall. The larger lower panel, and the smaller upper panel. Once they were removed this is what I saw. Thankfully, they did insulate the walls when they built it. Considering some of the other work I've uncovered in the house this must have been a different contractor.

Now that the wall panels are gone it's time to remove the fiberglass insulation and see what we've got for framing underneath. This isn't a load bearing wall, so it was framed solely for integrity of the wall and mounting the wall board.

The top of the wall needs some additional framing to fully block it out. Here you see I've measured the space between the studs and marked it on the existing pieces.

Next is to cut down some stock 2"X4" to finish out that upper frame.

Here you can see the additional framing screwed into place.

The AC Unit breaks into two pieces. There's the cage that mounts to the building (seen here).

And the primary AC Unit assembly (which slides into the mounting cage for final installation).

The cage height is measured against the framing to determine the correct placement and where to cut. In addition, we need to leave enough space on the bottom to allow for additional 2"X4" supportive framing.

Here you can see a close up of the measurements marking the bottom of the AC Cage and the gap for the necessary 2"X4" framing.

Using a circular saw followed by a sawzall makes quick work of the center stud.

Now we're ready to test fit. You see two pieces of 2"X4" set on top of the central stud. These are to simulate the framing that will be added once we successfully test fit.

Here you can see me test fitting the AC Unit cage into the opening. The clearing doesn't have to be perfect. Here you can see that the cage fits well within the planned opening. You'll note that It's being mounted very high in the wall. This is to allow the shelving which was underneath to be replaced afterwards.

Since we know everything will fit, it's time to add the remaining supporting framing. I've put in a double cross brace with extra studs tied in to the outer studs. This should provide more than enough capacity to support the AC Unit.

With the extra studs in place the cage was set back up to the wall and traced. I then used the Sawzall to cut out the traced outline. From there it was a matter of test fit the cage and tweak the opening as required. Remember, it's always easier to cut too small and widen rather than too large and have to figure out how to close it in.

Here the AC unit cage is now in place within the wall.

There's a top retainer for the unit. It's traditionally used for window placement and buts against the base of the window when installed. I've flipped it around and reattached it. This way I can drill into it and bolt it to the header for extra support.

This particular unit came with support brakets for the exterior. Here you can see the braked installed into the two by four. With the wall mounting I had to add a little trimming to the bottom of the opening for the bracket to fit correctly.

With the brakets bolted down and the cage replaced, the brackets can be mated up with the cage and finally installed into the wall.

Now, there wasn't any wiring in the wall to support something of this size (it's 220v, not your normal 110). Here you can see that we've started fishing romex through the wall. This will go up, through the attic and out to the circuit breaker. And man, if I thought the garage was hot, it must have been 120 degrees + in the attic running the cable!

If at all possible, always plan for the future. Here you can see the breaker that will be installed. Now the AC Unit is a 20 amp unit, but I eventually want to put an enormous air compressor in the same area, and will need 220v for that as well. This breaker is rated for 60 amps, so I'll be able to easily add an Air Compressor to this circuit.

Via the magic of the internet, the wiring's done. (it took at least an hour to get it all run and hooked up correctly).

With the help of a couple friends (it took 3 of us to lift/guide the unit into place)the AC Unit is installed and running!

To give you an idea of the power of this unit, my garage was 90 degrees at 10pm when we started the unit. By 11pm it was 77 degrees. Boy what a difference!

Aside from the AC unit, insulation is the most critical factor to keeping an area cool. Here you can see that I've filled the gaps around the unit and the area in between the unit and the studs with expanding sealant foam. This stuff expands to fill voids, it's pretty cool stuff. (It's also instanely sticky, so don't get any on you!)

The insulation is trimmed down and put back into place. And yes, I know the fiberglass is reverse of the original. The paper side should face towards the living area.

The wallboard has been trimmed to fit around the AC unit and nailed back down to the studs.

The final bit of wiring is done, the cover is now on the electrical outlet.

Finally the rolling shelving is now back in its proper spot. I've got a good couple hours of cleaning up / neatening before everything is completely back together, but at least now I can do it in cool comfort!

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Contents copyright 2008, 2009 - Jody F. Kerr

All references to They Might Be Giants are fan references only. John & John I hope you don't mind! And if you're ever in Phoenix stop by for a visit!

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