Looking into A/C options for shop

[signcrafter]

Just got my shop heater installed, still have to run the gas line but it's hanging and vented so will be working before temps really drop. But want to start looking into some sort of A/C to install in the spring or this winter if weather allows working on it. I have a 1200 or so sq ft shop with half having 8' ceilings and half having around 10' ceilings. Walls and ceiling are insulated. Shop is in Wisconsin so it gets in the 80-90s and can break 100 one or two weeks a year usually. But humidity is really high so hoping A/C will help deal with humidity.

What are my best options for cooling off and getting some of the humidity out of the shop? Have kids so garage door probably will get opened or be open a few times a day when they are playing outside. So that would let all the hot humid air in anytime that happens but would like to get something that gives me the option to make it a little cooler when the doors aren't open. Would a mini split handle something like this and work for what I want? Or what other options should I look into? Just trying to do some homework at this point so I can start gathering whatever I need and be ready for next summer. Thanks

 

[zkdiesel]

A 3 ton regular air inside unit covers my 40x60 well with being smart about pulling in hot vehicles.

 

[Mikes61]

I just installed a Mr. Cool Advantage 36,000 in my 1500 sq ft garage. I’ve only ran it for a couple hours but it works great and will heat and cool. It has a “Dry” mode that pulls the humidity from the air inside.

Something to look into.

 

[chinboys]

Get a manual J calculation done to get the approximate tonnage of cooling.
Keep in mind on how leaky your garage is as much of the heat and energy gain in the Summer is via convection heat transfer.
Keep the structure as air tight as possible.
Also the most energy used during cooling is the removal of the humidity, latent heat,relative to the dropping of air temperature, sensible heat.
And use ceiling fans to circulate the air.

 

[fitter30]

RH flows from high to low just like heat. The tighter the structure the lower RH. Good garage door seals are a must.

 

[dcg9381]

There are two default answers to most questions on GJ:
1) 90A MHF
2) A mini-split

OP, your answer is #2.
How much mini-split depends on how well insulated your 1200 feet is and how quickly you want to cool it (BTU size). And how often you want to cool it (BTU size and efficiency). SWAG is 24k-36K BTU based on limited information. Yes, mini splits do this all day long. They're directional though, so moving the air (fans) might be helpful. And heating it you need to pay attention to cold weather capacity, because they don't all work the same below 30 degrees.

I've installed 24k in 600 sqft of garage. Standard residential insulation and a terrible garage door.
And I've installed 48k in 2400 sqft of garage. R15-ish closed cell foam. 3 horrible non-insulated roll up doors.
Both in Texas.

Both work fine but neither is real living space. How quickly they cool is different.

 

[rockcrawler]

I have two 24K Pioneer mini splits in my shop (35x45x14 w/2 10x12 garage doors and 2 man doors) and they work great here in Texas.

 

[WildBill]

I love my 24k Mr.Cool diy setup in my 900sqft shop, works amazing.

 

[rockcrawler]

With 1200 sq ft and low ceilings, you may get away with just one 24K mini split. Maybe a single 36K unit if the 24K is not enough. You’ll need to do some calculations to figure that out.

 

[aggie113]

Started with a 2 ton Gree mini split for my 30x40x18 garage. 2" closed cell foam and insulated garage doors and it can keep the garage under 80 (set to 78) during the Texas summers. But... open up the garage door during the day and bring a hot car in and it will not be enough. Found a good price on a Tosot (Gree off brand) unit 3 ton and installed closer to where the cars sit on the lift so I can quickly cool the garage back down when needed.

 

[Steve W.]

Installed a 24k Pioneer unit in my 24x30 building just a month ago. Had a couple warm-ish days soon after, am very pleased with the cooling results. Looking forward to some cooler days to see how the heat works (it's rated to -13° F). The (very) few times it gets below zero here, it's only for a few days, so I might not have to drag out the old kerosene torpedo that has been working very nicely for the last 10 years.

.

 

[signcrafter]

Garage came mostly insulated and I'm guessing it's not sealed the best. I still need to insulate half the ceiling in the next week or two. Just going to get some R19 faced batt insulation for now and then will do blown in probably next year when I have more time.

I don't mind working in the heat but the humidity is what kills me so if I can just keep it at a decent temp and keep most of the humidity out I would be happy. I'll have to do some more homework and see if I can figure out what size mini split will be best for me. Would it be better to get 2 small ones or one larger one or doesn't really matter?

 

[mrhemi426]

My shop is 26' x 48'. I built it with radiant infloor heat. After being in the home for a couple of years the humidity in the shop became a problem, both for comfort and for the well being of my tools and car collection. I now have a Mitsubishi mini-split (cooling only) in the shop that works great. It has a humidity control mode that I use most of the time. The shop is very well insulated so I have not noticed much increase in power consumption with operation for the summer season.