Concur. A 1 ton unit would get the temps down fine, presuming the building is sealed and insulated well. With energy costs up and potentially rising in the future, the best solution is improved insulation combined with a smaller unit.

I have 2 ton (24000 BTU) ducted split A/C systems cooling 1100 square foot rental homes in North Mississippi. The outside temps rarely breach 100F, but the real load is the humidity. A 2 ton unit for only 400 square feet is certainly good for those with money to burn.

Anybody that lets their home get up to 110 degrees in the daytime is a total fool. I would be surprised such homeowners even exist, but then again...

I suspect that little portable will not even be close to meeting your needs. It just won't crank out the btu's you need.

Many years ago when I lived in an old brick apartment with a black flat roof, I left the window units off for a few days when I was out of town and came home to all the candles in the house slumped over like drunk chick puking in a trash can. How hot does it have to get to soften candle wax?

A friend with a 24 x 28 attached garage simply tapped onto his house hvac. The house is on a crawl space and he went through the lower garage wall into the crawl space on two sides (back wall and one side wall that were both common to the house). He installed standard AC vents with 8" flex ducting and tapped into existing duct lines in the crawl space. No return - just the two vents. The garage and door are insulated. It works great winter and summer and is in a humid climate. Very simple to do if you have an attached garage.

I don't know how hot, but the idiots at Disney World gave my kids crayons once while we waited for our reservation to be 'fixed'. Of course the kids left the crayons on the back seat of the rental car in the Florida sun, and, well you know what happened next....

Somewhere out there there is a mid-sized GM car with a crazy red-blue-green-purple stain in the back seat.

I guess I take my moderate climate for granted. We hit 30*C (86*F) a few times in the last couple weeks and that is considered exceptional "talk of the town" stuff. We are a 5 minute walk to the beach, so we have a swim right after work to cool off.

When it does get too hot in the garage, I find running the dehumidifier is all it takes to make it comfortable.

Not sure I'm understanding you here. If I get a 12,000BTU portable, will that be the same as a 12,000BTU split or 12,000BTU window mount, or are they all rated differently? Looks like 12,000BTU portables are available, but I want to be sure it will do the job.

To answer some of the other Q's -

- it's an attached garage, but I can't tap into the home A/C because the home is so well insulated we rarely even run the A/C. Maybe 2-3 times a month in the summer.

-House is near Sacramento Ca, so hot and dry. I did consider a swap cooler but I've heard many coworkers who grew up in the midwest say they can cause mold and rust. I've got a milling machine, tools, computer, and of course the car in there, so I'm worried about corrosion.

I really appreciate all the feedback. Thanks.

My bad. I thought those portables only were 5-6K btus. I just did some research and see that you can get 12kbtus and up! You are correct in that a btu is btu.

Summer's coming so I thought I'd revive this thread.

My garage is 22 x 43 (946sqft) and I could cool it decently with a 2 ton window unit. After three years the unit is not cooling very well. I'm pretty sure I just need to take it to a shop, have them add a coolant tap and recharge it, but:

Since the window unit only cooled pretty well and is very loud I'm thinking about installing an attic system. Anyone out there in Pelicanville have any DIY experience with this?

Anyone?

Insulating to keep the heat out!? Now I've heard everything!

Why not go for a Japanese/Korean split system?

I assume you're talking about a ducted split system (ductwork, attic air handler, and outside condensing unit). It's not a DIY job unless you already have the tools and knowledge.

If you can adequately move air around the garage with fans and such, the ductless split system (hotel A/C) will be cheaper to install (equipment and labor).

Once you account for the possible need for extra electrical wiring, you might find that you can cool the garage with 2 smaller window units. This may allow you to use existing outlets in the shop, as well as offer better distribution of cooled air, particularly with the 40+' length. Divert the dollar savings to better/more insulation.

It all depends on your budget and needs.
Jurgen

Wiring shouldn't be a problem since I already have 220V to the current 2 ton window unit.

The Mitsubishi ductless unit at mrslim is $2300 and I'm trying to come in under that. Plus I'd like to A/C outlet to be higher than my vehicles so it's not blocked when the garage is full (my truck will block the current unit if I pull it far enough forward to make room for a 996 :D)

My thought is a 2 ton compressor outside and a 2 ton air handler without heat in the garage attic. I think I can buy the two items for under $1500. Then comes the issue of ducts and freon lines. I've never dealt with A/C stuff so I don't know the best way to go.

Do an eBay search for '2 ton ductless' and click "title and description.' You can get them for around $1250, precharged, and ready to install. It wouldn't take more than a day to install. If you needed heat, then I'd go with the regular split system with ductwork. With the ductless unit, mount the inside unit anywhere on the wall.

$1500 sounds a little high on the 2 ton split, but don't forget the plenum, ductwork and copper lines. That will bring you up a few hundred, and then you still need installation.

Mitsubishi is the top of the line, I meant it as a reference only. There are lots of cheaper Korean models out there.

http://www.ductless.ca/ac/lg.html

It looks like the ductless unit has a separate compressor and air handler. I wasn't catching on to that.

If that's the case, I can have the compressor nicely hidden below the fence line but still mount the air handler high on the inside wall so it clears the cars.

Maybe I can get a deal on the Mitsubishi unit through my Mitsubishi turbine buddies :)

EDIT: I looked around at prices and it looks like for a 2 ton unit I'll have to spend at least $2200 for an A/C only unit or $2700 for a heat pump. Then tack on a couple hundred more for wiring, tubing, and coolant.

That's a lot more than I was planning, but it looks pretty portable so if we move I can take it and just have to patch up a little hole.

They are very effective. And quiet.

But pricewise you can't beat a window unit.

I just found this 2 ton unit for $1149 http://www.ehomeair.com/index.asp?PageAction=VIEWPROD&ProdID=27

Things are looking up :)