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Mini-split AC for garage.

jeepthrills01

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Anyone in the desert SW have a mini-aplit AC in their garage?
I'm considering one...and probably a DIY project...except for the electrical...(they come pretty set up lately).

3 car roughly 25x32 with a 9.5' ceiling.
I'm coming up with like 24k for BTUs.

Any experience welcomed
 
I think you'll need more than that for a desert location. I see mobile homes out there with two 5-ton units on the roof.

We have several mini splits on residential apartments, they work well, and are really easy to install.

Tom
 
Anyone in the desert SW have a mini-aplit AC in their garage?
I'm considering one...and probably a DIY project...except for the electrical...(they come pretty set up lately).

3 car roughly 25x32 with a 9.5' ceiling.
I'm coming up with like 24k for BTUs.

Any experience welcomed
I like that some inverter units have SEER ratings in some 20+, very impressive.
Another idea to assist is a hybrid electric heat pump water heater to get some 24/7 precooling in the garage if your house/garage is set-up for it.
 
I have a 36k in my 28x40 in SC and while it does fine it could have been bigger.
 
My shop is 18x31 with an attached 12x12 with 12 foot side walls. Double bubble aluminum backed heat barrier insulation. I have a 24k mini split it does fine with the exception of the interior of the top 4 feet gets warm if I don’t run a circulation fan. Pensacola on the gulf coast. Summers are 76-80 at night 95 days. A/C’s are real water makers down here. I keep it set 80 summer 66 winter, it keeps the rust off equipment cars and tools.
 
I have a 2 ton (24,000 BTU) Mitsubishi mini split in a 25x25 insulated garage (insulated) in Arkansas. It’s fine as long as I leave it running on a moderate setting during the summer. But park a hot car or two in there and it will take a while to recover. For your location and size I think you will need something bigger. I also have a ceiling fan in mine that I leave running on low speed to move the air around as that one mini split outlet doesn’t provide a lot of air flow in a space that large.
 
Insulated garage? Otherwise forget it. Are you going to do all the a/c work including filling the refrigerant charge?
 
I have a mini split in my garage 25x28. Not exactly sure of the btu. Much the same as AR67GTX results. I imagine in AZ they probably do better as they don’t have the water to remove.
 
Not really applicable but, I installed a 1 ton mini in my shop (28560 cu ft) basically for dehumidification. The temp without it stays around 70* on the hottest days here in MI but, it does help with cooling too.
Mike
 
My garage is 1130 sq ft and has 12.5 ft ceilings. I have both swamp and a mini split. The mini split is a 3 ton Gree. I was told regardless of brand name all mini split are manufactured by Gree.

Anyhow, the mini split works fine on triple digit days IF you keep it on to maintain a temperature. I program it for 82F on weekdays operating from 9am to 9pm. Then on weekends, or when I'm working in the garage I'll manually set it for 77F.

If you have a hot garage on a triple digit day it will take about 8 hours for the mini split to cool off. The "turbo" mode seems to be a gimmick as I believe it cools best with the vents pointed upward and automatic fan.

I'm a little disappointed the mini split can't cool off a hot garage, but if you maintain a temperature all the time they do seem to work well and electricity wise seems to be really efficient.
 
Installed near ceiling.

IMG_20250606_064051949.jpg
 
Mine is up at the ceiling too. Also my ceiling fan is shown. If it goes out I may look for a little larger one but I have to keep clearance for the car on the lift. I agree with all of the above comments on trying to cool down a hot garage. It takes quite awhile. Sometimes I run it at night and turn it off during the day as it stays pretty cool in the spring and fall during the day.

IMG_1397.jpeg
 
Really depends on how well it is insulated. My shop is in Cincinnati and is 5600 sq ft. Very well insulated. It is way more difficult to heat than cool in Cincy. My 5 ton (conventional heat pump) does just great, and it does not have backup heat hooked up. Yes - you are in a much hotter area, but your square footage is small. It really depends on your level of insulation.

Below is the mini split vendor I use. So far my cousin and I probably have bought a dozen and we are happy with the results. Much cheaper than the main stream units. They are made by midea and gree (typical for many mini split vendors).

Call the vendors and see what they say. My experience is they many times size it larger than necessary. With a mini split its not as big an issue, but its usually better to be on the smaller side of ac unit than too big.

 
And to show how well my shop is insulated, its been in the upper 70's to 80's here. Not been in the shop for a few days. Went in there yesterday and it was a very comfortable 72 degrees. The AC is not on, but dehumidifier is running (2 of them - one in the main bay and one in the car storage bay). I have 8 large overhead doors in the shop. It has 14 foot ceiling.
 
I have installed 4 or 5 of them, pretty easy job, the ones I did came pre-charged with refrigerant. Harbor Freight sells a cheap vac pump to evacuate the lines before you charge it.
 
Insulated garage? Otherwise forget it. Are you going to do all the a/c work including filling the refrigerant charge?
Most of the units I have come across (Mitsubishi, Toshiba, Pioneer) all are shipped with charged condenser, evaporator and lines.

120v isn't going to cut it...this I know. At one point I was considering a pair of 15ks, one on each side of the garage. But sizing up to a 220v system makes alot more sense.
 
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They are not hard to install, but sometimes the flares are tricky to keep from leaking especially if you have to flare them yourself. You do need to evacuate the system well. I shoot for 50 microns which I achieve regularly on soldered joints but struggle to get to on flared mini-split joints. Typically get to about 70 microns on mini-splits.
 
They make a flare gasket (FlareMate) which I hear works well. They are pretty simple. But yes, 220v would be my choice.

The most I was able to pull on a home system was around 340 microns.
 
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