Garage AC calculation help

[cgrandahl64]

Hello, I am not too schooled in heat/cooling calculation and I am hoping to buy an AC today and get it installed. I tried using some online calculators but had no luck. So I figured I would ask the forum and see if someone can give me a quick answer.

Located in southern MN.
The shop is 46.5’ long x 22.5’ deep x 9’ ceilings.
Three garage doors. Two 9x7’, one 9x8’. No windows. Insulated with an R value of 18.4.
One insulated service door 36” wide.
No windows in the garage.
Walls R value – R-22
Ceiling – Fiberglass blow in R-40+
Building is tight – full moisture barrier with taped seams
Attic is vented from soffit to peak and gable to gable
Exterior is steel, pole barn style, walls and roof.
Slab is 5-6” concrete with no insulation.
There is limited shade. And the garage/service doors face south.

I’m really looking to get cut the humidity down and get the shop to 68-72F when it is 95-100F outside.

I plan on mounting a through wall ac unit in the middle of the 46.5’ back wall. I have ceiling fans on a speed control so I should be able to have decent circulation.

I am looking at the Frigidaire units at Lowes – need help deciding between 18,000 or 25,000 btu.

Any suggestions, opinions etc.?

Thanks,
Clint

 

[pattenp]

I think the 18500 BTU unit should do seeing that your garage is well insulated. The 18500 will do better removing the humidity than the 25000 because it should run a little longer. If the 25000 ends up being to big it may run short cycles and not remove moisture from the air as well.

 

[cgrandahl64]

Thats what I was thinking..
No matter what the 18000 btu will cool it down, and if it has to run a lot it will be dryer and feel cooler - no matter what it will be a huge improvement over nothing.. guess im going to lowes over lunch..