Window AC Unit Recommendation?

[BQuicksilver]

I'm looking for advice on the future purchase of a window AC unit.

I have an older home (Indianapolis) with attached 400sq ft garage (20x20) with no insulation currently. It has old sheetrock and brick currently with no ceiling...just visible rafters without insulation. I'm in the process of gutting out the walls and installing R13 batts and new walls. I'll be retaining the old (leaky) doors and lack of ceiling for the time being. The garage sees partial sun.

Questions:
1) I've estimated that 12,000-14,000 BTU would be about right considering my insulation situation. If that is still excessive let me know.

2) What brands do you recommend, and what features should I look for (beyond the effeciency rating of course)?

3) About when have you noticed them getting cheap at the big boxes? This late in the summer I might as well tough it out and pay half as much.

4) Considering cool air is heavier, how much will the ceiling situation hurt my efficiency? I'm sure it will be a big issue with heating, but will it affect cooling heavily?
Thanks!

 

[DynoDave]

Good timing BQ. I'm about to cut the plywood out of the framed window a/c opening in my back wall. I want the siding to fit snugly around it, so I need to know what unit I'm buying, to know how big the opening is.

 

[oldgoat]

I bought the Samsung 18000 btu from Lowe's for my 22 x 26 with 9ft ceiling. I think it might be overkill, but I figure I will want it to be able to cool it down quickly instead of taking a lot of time and I would be more mad buying too small of one and not having the ability to cool down the garage in a reasonable amount of time later when we get the 100 degree weather. I am going to put it throught the wall and the factory said that I could on the 18000 but on the 12000 they didn't recommend it. You do have to make sure that you keep the vents clear for it to work like it should. Hate to cut the hole in the wall but I hate more having to spend a lot more on AC.

 

[Steve in Mi]

4) Considering cool air is heavier, how much will the ceiling situation hurt my efficiency? I'm sure it will be a big issue with heating, but will it affect cooling heavily?

A bunch and yes. The money spent insulating would have been best spent doing the ceiling first at least on a per square foot basis. Insulate first where the temperature difference, inside vs. outside, is greatest - without any insulation, that generally is the roof. This is also the reason that ceiling/roof insulation is applied at 2X, 3X the sidewall "R" insulating value.

 

[DynoDave]

Any other thoughts, guys? Especially to questions #2 and #3?

 

[hotrod66paul]

Menards in INDY has all the window A/C units on sale now. I live on the west side of Indy and was going to put in a window a/c unit but Meijers ran the Sunbeam portable units on sale last month for $199.00 each for the 9,000 btu units plus 20% off with a coupon. The window units were cheaper per btu but I like,d the idea of not putting holes in the walls of the garage (no windows) .As far as no ceiling insulation you might try stapling a cheap tarp up to help hold the tempdown. Just an idea.