A/C In The Garage - Good Idea
 

Hello. I have a 2 car garage Villages home.

Has anyone installed air conditioning in the garage? What would you recommend? Would a mini-split do the job? Or, would a portable unit such as they sell at Best Buy work?
Thanks in advance.

You will need to add insulation to the ceiling area of the garage, and this maybe complicated if you have attic storage. You will probably want (need) to insulate the garage door. IMHO, I would definitely go with a minisplit. Most if not all of the ones I looked at required 240volts at 15 to 25 amps which typically require a permit and licensed electrician. I know there will be several who will disagree and state that you can DIY but I believe there are limits on the type of DIY electrical work. Also, I think FL requires a license for the refringent lines. As for the portable AC unit, you cannot use a window AC unit, you may get away with a window exhaust type unit with the large flex exhaust hose. Be sure to look at the customer reviews on these, and also figure on where and how you will handle the drain line.

If you are considering a portable unit, I would not believe the square footage coverage that they claim. You will probably need a much larger unit. But, one advantage to the portable unit is that it can be moved to a bedroom when needed.

By the way, the portable units that sit on the floor with a round duct through a window are allowed, according to ARC. Window units are not allowed.

I have done this in my 2 car w/golf car garage, 3.5 years ago. I had a mini-split installed. As Villagethinker suggested, I did insulate the garage door, as I have an East facing door, that made a huge difference. I also had the garage door windows tinted. I elected not insulate the ceiling because it was already set up for storage and I was not sure I would gain as much since heat rises and want to let that out. I shopped around on the mini-split and opted to go with Munns, the did my houses HVAC and they had the best value.

I did this because my garage is also a workshop for both my model building, where I have a small spray booth and also for my 10 needle embroidery machine and 3D printing. Adding this added about $15-20/month to my electric bill in the summer months. I typically have the space set for 74* and it recovers nicely when the door is opened for a long period of time. My main purpose for this is reducing humidity in addition to making it more comfortable.

I would suggest that you reconsider not insulating the ceiling. You are losing a lot of energy through the roof.

We added a mini-split to the garage and it works without any additional insulation, just sayin’.

If it is sized large enough, it may work fine, but you are losing a lot of energy and spending more money on electricity. No builder or building code writer would ever allow a house to be constructed that way.

When we built we added an insulated garage door. We had Kalos insulate above our garage and install a Mitsubishi 24k BTU mini-split. All in it was about $7k.

For those that did the mini split, what was the approx cost to install. My walls are precast concrete.

It’s a garage.

NFM

Yes, heat rises, but an uninsulated attic that is easily 120° much of the year separated from the garage by half an inch of drywall with an R value of less than one radiates a LOT of heat, like a hot oven does or a hot car. If you don’t need to insulate an attic over an air-conditioned garage because heat rises, then why does the rest of your house have insulation in the attic? In your garage, the cooled air comes into contact with the hot drywall and is heated up.

I agree. The insulation above the ceiling is absolutely the most important insulation in your house, but only above conditioned spaces. So, if you install a mini-split unit in your garage or in your lanai, you need to install at least R-30 insulation above the ceiling. The more the better. Having no ceiling insulation is like trying to fill a bucket with water when the bucket has a large hole in the bottom.

We did it…
 

We have a three car garage and we sprayed the ceiling of the attic above as well as have insulated garage doors. It’s awesome! The garage stays very cool and the attic is a decent temp for storage. We installed a mini split and hired one of the local companies. Be careful…we got three estimates and they were wildly different…by thousands! We settled with sunshine. Installation was great and they were very easy to deal with.

Our garage is east-facing and over 1,000 sq ft. We installed a mini split (from Munns) about 4 years ago and did not add any insulation to the storage/attic area above it. However, our garage door is insulated. It is absolutely amazing how quickly that mini split can cool down the garage (and keep it cool) - even during the hottest days. It only takes about 10 minutes before the temperature reaches the selected level. In addition to storing 3 cars and 2 golf carts, we have a small workshop in one corner, a workout area (treadmill, Peloton bike, dual-rack functional trainer [cable machine], free weights] in another corner and a golf simulator/launch monitor with 10x15 foot movie/TV screen across the back. Whenever we want to use any of those or just work on our vehicles, we simple turn the mini split on and wait 10 minutes. Once it is cooled, doing anything in the garage is completely comfortable. We do not cool it all the time - only for extended use activities as noted above.

I’m not sure if the outside walls are insulated. Am sure that the attic is not. What about the garage door and the lack of real seals on the edge? Doesn’t sound very practical, but if it floats your boat, do it.