Window air conditioner - or mini-split - for my garage?

[Baz]

(edited title to include mini-split - see post #5 below)

I'm interested in trying to control the climate conditions in my garage - mostly the heat and humidity. We get some cold weather in the winter but not that bad and probably not worth addressing - for now anyway.

I'm in Florida with a 2 car garage, no vents, flat roof treated with a white silicon product, 2 windows, a man door, and a fiberglass garage door.

The garage is at ground level connected to the house without a door - the house sitting up on a dune ridge.

In addressing climate control, I realize insulating the garage door is a popular approach, but for now, let's avoid any discussion of that approach.

One of my concerns with installing any venting - is allowing the salt air and humidity inside, which of course leads to corrosion issues.

So I'm thinking for now, a window AC unit would be my best approach.

Something in 110v so I can just plug it in. I have 220v in the garage but only large enough service to run my irrigation pump.

I have a remote sensor/thermometer so I see the temps every day and would like them to be lower - maybe 10 degrees would do - or less on some days. Right now showing 80 outside, 87 inside the garage, and 90 in my attic.

I'm not trying to make it comfortable like inside my home - just slight modification.

Has anyone here done this and if so I'd appreciate your thoughts.

Thanks, as always!

[Baz]

An older pic of my house - you can see the flat roof garage. The 2 windows are facing toward my boat. Garage is concrete block....

[stevej37]

I don't have the heat here that you do...but sometimes the humidity is bad.

The dehumidifier that I placed in the garage makes it feel like 10 degrees cooler. In the summer I have to empty it every day. Humidity is bad for older cars.

[Roswell]

Baz,

Installed one of these in a bonus room this past spring. Very pleased with its performance.

https://www.amazon.com/Midea-Inverter-Conditioner-Flexibility-Installation/dp/B0867GMW9X/ref=sr_1_3?crid=IAH8350W6LX0&keywords=midea+12000+btu+air+conditioner&qid=1658086705&sprefix=mid%2Caps%2C85&sr=8-3

[Baz]

Thanks for the replies so far!

I was thinking about the fact that both windows are not centered - so air distribution won't be balanced.

Then I remembered at one time I had considered a ductless mini-split. They make 110v units.

Here's one on eBay for example:

12,000 BTU System Ductless Air Conditioner,Heat Pump Mini split 110V 1 Ton w/kit

12K BTU and only $424! Plus it also heats....

[hcoles]

Fine with me if this turns into a general mini-split thread.
For example - what brand to buy if you later need service after DIY install? I don't want to pay for all the busy work.

[look 171]

Baz, mini split all day long. They are more efficient, have heat too if needed. I normally buy Lenox for clients (great warranty) but installed samsung in the past without any issues for over 7-8 years now. Sam sung now has a ceiling mount blower that looks like a vent instead of the big old thing hanging on the wall. They even offer a picture mount, the blower is square, very slim, 3-4" thick with air blowing out of all four directions. There's a bit of space that allows a picture or photo to be slipped in on top making it looking like a picture frame hanging in the hall way. cool stuff

[908/930]

Is the ceiling in the garage insulated? If not I would start with that. Any AC unit will help get rid of the humidity, sizing to keep it cool is a little harder. For reference those small electric heaters 1600w produce about 5500BTU, so on a cold day would two of those be able to heat up your garage?

[Baz]

I was doing some reading on You Tube videos and a point was made about SEER ratings on these inexpensive 110v eBay mini splits.

The one I mentioned above has nothing about SEER on it's auction site and on one of the videos the author did a calculation and came up with approx. 13, which isn't that great. He also mentioned the condenser doesn't have the ability for variable speed - only runs what it's set for.

So I found another on eBay rated for 19 SEER for only $749.99:
9000 BTU Ductless Mini Split Air Conditioner and Heat Pump 19 SEER 110 VOLT

And another which is 20 SEER for $819.99:
12000 BTU Ductless AC Mini Split Air Conditioner and Heat Pump 20 SEER 110 VOLT

Now I'm thinking either of these would be a better choice.....

[red-beard]

Most mini-splits are variable speed drive with much better dehumidification and lower power overall than a window unit.

That said, a small window unit is CHEAP. If you aren't using it all the time, those other things will matter a lot less.

[lindbhr]

I bought a Senville mini split for my barn/shop. It works great. Have a look at their website.

[Seahawk]

I have done both.

I do not do any work in the garage connected to the house. I have a ton of workshop space I use in separate buildings.

James is the expert but after the mini-split stopped working in the shop, I replaced it with a window unit to cool and heat two bays very cheaply compared to replacing the older unit.

I do augment everything with fans, btw. It works. Maryland get hot and humid so I know the drill.

I also have a smaller shop that is directly attached to the barn shop that I have cooled with a small window unit for over 20 years - same unit. I was up there for hours today getting organized and fingers crossed I get to 21

Do you still live in the house in the photo? Nice.

[look 171]

Originally Posted by Baz

I was doing some reading on You Tube videos and a point was made about SEER ratings on these inexpensive 110v eBay mini splits.

The one I mentioned above has nothing about SEER on it's auction site and on one of the videos the author did a calculation and came up with approx. 13, which isn't that great. He also mentioned the condenser doesn't have the ability for variable speed - only runs what it's set for.

So I found another on eBay rated for 19 SEER for only $749.99:
9000 BTU Ductless Mini Split Air Conditioner and Heat Pump 19 SEER 110 VOLT

And another which is 20 SEER for $819.99:
12000 BTU Ductless AC Mini Split Air Conditioner and Heat Pump 20 SEER 110 VOLT

Now I'm thinking either of these would be a better choice.....

Don't over think it. Its a garage. How much time will you be spending in it? Do you even care if seer rating past building code? If you get up to 17 seers, I think you are in good shape. I can't keep up with seer ratings anymore. They seem to up it yearly for efficiency and code. The older ones just do not move and sits in their warehouse. Try and get after those for a good price.

If possible, get the 240V units. More efficient

[rfuerst911sc]

Hands down mini split . I heat/cool my 24x26 man cave garage year round . My ceiling is just under 12' . Silent/efficient and not too hard to DIY install . I prefer a 220 volt vs 110 to help keep electric bill lower . It costs me 20.00-25.00 a month and I run it 24/7 .

Tons of brands and sizes available , I am partial to Mitsubishi . Mine is a 24k and I installed the same one in my previous homes garage . They perform very well and are high quality .

[cabmandone]

What are the dimensions of your garage? I use a Delonghi Penguino for my 24x40 when I have family over during the summer and it's hot out. It's an 18000 btu unit so ton and a half. I need to turn it on at night when the sun load is at its lowest. I run it pretty much all day to keep it at temp with two garage doors and three windows.

[URY914]

The central Florida heat and humidity doesn't compare to anything anyone else responding here experiences. Baz, you should be able to find an old window unit sitting out by the street if you look hard enough.

[Baz]

Thanks for all the replies and input so far.

Answering questions.....the ceiling is currently open/exposed joists. It was plastered but when we did the re-roof I removed the plaster. I prefer the "look" of the open joist plus can stick stuff up there easier and attach hooks and brackets easier. I realize insulating it would help and will consider that down the road, thanks.

Yes, Paul - still live there. Lot more foliage now on the property though.

Right now I do not do any work inside the garage - it's just to store my 356, one motorcycle, tools, a mini-fridge, and other assorted items.

I do keep 2 of my surfboards in there too hanging from the ceiling in 2 rope loops - easier to pull in and out as needed.

I have a 30'x12' outside storage area that is covered but no sides and plan to enclose it this winter. Also some storage space under the part of the house that overhangs. When I get those areas ready, I will move all my garage stuff into those areas and free up a lot of space, potentially giving me more room to work on things inside my garage. So what I am doing today will help matters down the road. For now I just want to ease up on temp and humidity.

I know a window unit would be easier to do and may even do what I'm looking for - for now.

I will give some more thought. I actually have on hand both 5K and 8K BTU window units brand new in their boxes as backups for power outages for inside the house. I keep a 5K installed year round anyway for just such emergencies. They are all 110v with plugged cords, which is what I will use in my garage.

Long term I think the mini-split though would be ideal for me, all things considered. So may buy one and keep it in storage until this winter when i get further along.

I don't have any idea if prices on these will go up or down. Most things are going up so wouldn't mind getting one before they go up.

Thanks again for all the comments, suggestions, and feedback - truly appreciated guys!

[cabmandone]

IMO, in your climate, without insulation in the ceiling, you're wasting your time and wasting energy.

12,000 btu per ton. The roof load with no insulation in a climate like yours? The 5K and 8K won't keep up. I run a 18,000 btu portable, mentioned above, in my garage and it works hard to keep up in a fully insulated garage when I have guests over.

BUT! I'm just a guy with a background in HVAC... so I could be wrong.

[Baz]

Originally Posted by cabmandone

IMO, in your climate, without insulation in the ceiling, you're wasting your time and wasting energy.

12,000 btu per ton. The roof load with no insulation in a climate like yours? The 5K and 8K won't keep up. I run a 18,000 btu portable, mentioned above, in my garage and it works hard to keep up in a fully insulated garage when I have guests over.

BUT! I'm just a guy with a background in HVAC... so I could be wrong.

No doubt that ceiling insulation would be ideal - but some factors in my situation that might be different than what's typical.

Roof is white in color from silicon treatment I gave it two years ago. The layer of silicon is over two-layered peel and stick which is over plywood. The white silicon has made a significant difference - as evidenced from my remote temp. sensor

Roof has shade all afternoon and some in the mornings from surrounding palm trees.

Also, the garage stays shut up most of the time and I don't plan on staying inside there so just trying to take the edge off a bit.

The garage also faces North so that helps.

Thanks for your input - it's greatly appreciated....

[Baz]

Recent photo....little dingy and will get a power wash soon. Note the shade. The garage sits down at ground level below where my house sits (see photo in Post #2).