Sizing a Garage A/C

L

LouisanaJeeper

New member
Specs:

25'x25'x10'H detached garage

slab floor

drywalled, but not insulated

20' non insulated aluminum garage door

summer= 90-95*, winter = 35-40*

wall mounted, all in one unit

Budget $250 for materials



it will not be run full time, just when I am in there for more than a couple hours.



I was thinking about 8,000-10,000 BTU unit, does this sound about right?
 
You'll never be able to cool that area in that climate for $250. What is hurting you is being non insulated. You didn't mention if it had any windows and if they were facing the sun (morning or evening), if the garage door insulated, and if the garage was shaded.
 
1 window, single pane approx 8'x5' with 20% tint on the north side (shade).



The garage has a 20yr old cypress tree on each corner (4 total), so it is pretty shaded.
 
It is very difficult and costly to heat/cool any uninsulated space. In the absence of insulation I would look for a whole house exhaust fan of some type placed near the roof or eave of the garage.
 
I would consider insulation. I have the same problem here in Texas. I want to air condition my garage. Since you walls are drywalled, you should consider one of the blown in insulations. I had a buddy of mine who rented a machine to insulate his house. You would basically drill a 1" opening between each stud and blow the insulation in. They use either fiberglass or a wood fiber material. It sounds messy to me so you might want to have some do it for you. Then you would need to patch the holes.



As for the door, Home Depot or Lowes sells an insulation kit for garage doors. The other option is to but the rigid foam insulation and cut it to fit in the door panels yourself.



As for the sizing I googled to http://oee.nrcan.gc.ca/roomaircond/size.cfm?PrintView=N&Text=N



Let us know what you decide.
 
It's really not that messy, i have done it before. You basically just stick the hose in the hole and let it fill. Every once in a while take a peek and see where you are. If you're really lucky, you migh be able to see down the top of the wall from the attic (or something similar) and not even have to drill holes, just shoot it right down. I have to agree though, insulation probably is necessary if you want to heat/cool the garage with any effeciency.
 
Thanks for the tips

well, like I said eariler, it will not be cooled/heated full time... mabey just 1-2 afternoons a week. I might insulate in the future, but I really dont see it making all that much of a difference in my application. I'm probably going ahead with the unit and leaving the option of insulation open to future improvement.
 
You're gonna need around 12,000 BTU's minimum.



If it's sunny and not well insulated, maybe you can boost up to 14,000.



Plus, you *may* need a dedicated line to run it depending on what else is running on it.



To save money, I'd buy a window unit and not a wall unit. You can install it in your single pane.



Look on ebay!



This puppy is brand new in the box:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=20711&item=3825797719&rd=1



I found a reconditioned 12000 BTU for $189 including free shipping

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3825493817&category=20711
 
My AC guy told me for a house you need 1 ton for every 600 square feet of space. I don't know if that helps or not...
 
My garage is about the same size and I've been thinking about doing the same thing. My thought is just having the cool air blowing on my work area is probably sufficient; I don't think the entire garage needs to drop to 75 degrees to be comfortable. Be sure to update how it works out.
 
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