No heat needed, AC question

[dante81_98]

OK, so this is not a heating thread. I live in Phoenix, I don't need any heating for my garage. Instead, I would like to get some ideas on what to do for cooling. I have a standard 3 car garage. What are some of you doing for cooling?

Thanks,
Chad

[DaveL.]

Here was my simple solution. 17000 btu wall unit. Cools the 1200 sq ft garage with ease.

Dave

[bmwpower]

I put in forced air gas heat, so I added an A/C unit to the system. Probably overkill, but it's a 2.5 ton unit. I went with a bigger heater, too, so this supposedly was the smallest A/C unit that would work with my setup. I have yet to use it in the summer heat since it was installed in the fall. If you open your doors a lot, depending how big your garage is, a small unit might have a hard time keeping up.

[REFLEXX]

LG window AC units form Home Depot. they go up to 25,000 btu. Consumer Reports top rated and come with remotes. The price is great too!

I bought three for my project and made openings especially for them (not to lose any window space)

[dante81_98]

thanks for the replys. I don't have any windows in my garage, so a window unit would require a cut wall. I will stop buy home depot and check out those units.

Thanks,
Chad

[budfeigel]

Generally, A/C is computed at one ton of cooling per 500 square foot of floor area. Thats' for insulated spaces. One ton equals 12,000 BTUs, so a 1000 sq. ft. garage will take a 2 ton unit wether it be a "thru the wall" unit (window unit) or a A-coil on a blower/furnace. If the garage has open rafters/trusses and no insulation, I'd put in a 2 1/2 to 3 ton unit but you should consider a drop ceiling with insulated tiles. A/c is best if mounted high on the wall because the cold air will sink to the floor quickly and fill up the space. You don't want the unit to be too large or the compressor on the A/C unit will short cycle - run a short time and turn Off and On alot. Insulate, Insulate, Insulate. It pays back in the long term. Even insulate the under side of the floor slab too, if you live in a "cold in winter" area. This is done best with the Blue or Pink closed cell polystyrene boards of insulation laid out on the grade or rock before you place the concrete for your floor slab. Also highly recommended when you are going to do a heating system in the garage like a Hydronic System ( hot water tubes encased in the concrete.) Don't forget generous reinforcement in the floor slab to prevent cracking. More where the tires are going to rest.

Remember, putting A/C. in a garage will also reduce the moisture levels in the air; Good for reducing rusting on tools and other metal stuff like cars we want to keep for a long time.

[krooser]

I use a 35 + year old window unit for my 1500 sq. ft. shop. I think it's about 12-14K btu...not positive.

It will keep my shop nice and cool even on humid 90+ degree days...not as hot as Phoenix but the point is a window unit will do a good job.

Look at this unit...no idea on quality, performance or country of origin BUT it's a pretty neat design...http://www.store.yahoo.com/air-n-water/sospaircokf1.html

Here's more...http://www.store.yahoo.com/air-n-water/spaircosy.html

[JohnZ]

My garage is 2500 sq. ft., super-insulated, and I finally installed A/C last summer (my "retirement office" is out there too, so I want it comfy when it's in the 90's outside). Installed a 42,000-BTU Mitsubishi ductless split-system - only requires a 3" hole in the wall for the refrigerant and drain lines. Here's an album with all the details:

http://www.villagephotos.com/pubbrowse.asp?folder_id=1411059


I originally wanted a similar U.S.-made Carrier unit, but found out that they weren't making them yet (although they were advertising them), so I went with the available Mitsubishi unit. Both the inside air handler/evaporator and outside compressor/condensing unit are scary quiet, and it maintains mid-70's and low humidity regardless of the outside temperature.

:beer:

[dante81_98]

My garage is insulated top and 3 sides. The floor is not insulated, but to put it in perspective it was 81 degrees here on christmas day so I don't think that it is really needed.

JohnZ, that unit is really neat. I like it. I have a perfect place to put it too so that my HOA doesn't freak out. I will look into that.

Thanks,
Chad

[JohnZ]

That style unit comes in 18K, 24K, 30K, 36K, and 42K BTU models.
:beer:

[HotRodderAZ]

I live in Phoenix, I recently had a new A/c system installed. When I did I had them factor in my garage. They ran a duct just for the garage. It has been working great, very nice all year around. James

[BoostAddiction]

I've posted this elsewhere, but I have a 2-ton Daikin minisplit which is very efficient in terms of cooling with a 15 SEER.

My garage is 3.5 cars, well insulated and in the Mid-Atlantic region. So far it has done a great job.

Here is a pic:

http://i9.photobucket.com/albums/a70/BoostAddiction/6a3a48a0.jpg

If you run the unit much, the efficiency rating will be important. The usual suspects typically have a 10 or 11 SEER at best.

-Will

[sd formula]

I live in Florida so I don't need heat very often, but need a/c most of the time. I have a 3 car attached garage. (32'x24' with 11 plus foot ceiling, 1ea. 16' x 8/ & 1ea. 9' x 8' doors, cement block.) Luckily the doors don't catch the sun for most of the day. This helps alot. My house has a 3.5 ton Primary a/c unit, & a 1.5 ton secondary a/c unit. the primary unit covers the main area of the house. The secondary unit covers the master bed & bath & a 15' X 15' den. The volume that the secondary unit covers is approximately the same volume as my garage. The secondary unit usually isn't needed during the day. I put in a diverter system with dual flapper doors in the air handling system of the secondary unit. Thus, cool air (or sometimes heat) can be diverted to the garage when I'm out there. I simply make sure the unit is running and move the diverter arm to the garage position. I also have insulated the overhead doors with styrafoam & insulated the attic. The additional ducting was fairly short because both air handlers are in a small room above the garage ceiling. Ceiling fans also help circulate the air, as I only put 3 outlets in. The downside is that garage smells get into the house more easily than before. I also have a carbon monxide detector in the house area that the secondary unit services.

[Grimjaw]

Being that you are in the desert, have you thought of using a Swamp Chiller?

How it Works

Swamp coolers are an efficient and effective machine for cooling. As a direct placement for air conditioning in dry climates like Utah and Nevada, it is an example of how man can work with nature. Being so much less expensive than air conditioning, it almost seems that we are getting something for nothing. This short essay explains part of the fascination with the evaporative cooler phenomenon.
The way a swamp cooler operates is very simple. There is a low horsepower motor which pumps the water from the floor of the cooler to the top of the cooler, where it proceeds to fall down the sides, along porous filter pads. A second motor drives a fan which pulls air from the outside, through the cooler, and then pushes it into the hot room. The significant cooling action is the water evaporating as the air passes through it. (Incidentally, the water level is kept constant with the help of a floating sphere functioning similar to the one in the toilet bowl.) The hot air enters the cooler, where two small motors power nothing more than a fan and a pump, in order to send cool air into the hot room.

The way the air is cooled in the cooler, is similar to the way evaporating sweat cools the human body. We all observe this miracle and take it for granted, but to analyze this, it is helpful to remember the bell curve: When a substance is perceived at a certain energy heat level, measured in temperature; there is really a distribution of varying levels of temperature throughout the molecules of the substance. This assortment of temperatures average out to the measured value. Most of the molecules can be around the average, and the farther from the average, the less of them there are. For example, water at room temperature has most of its molecules at approximately that temperature. But it also contains molecules that are near the boiling point of water, and also near its freezing point; however small in quantity they are, they are an important presence. Because at the boiling point of water, there are molecules that are a gas and that are a liquid. The liquid molecules will absorb energy in the form of heat t o become a gas and escape the confines of its old form. As the molecules from the higher temperature evaporate, the remaining liquid averages less heat. But there will still be water at the higher temperatures because the remaining molecules redistribute themselves along the bell curve, which enables the next molecules to evaporate. Heat is siphoned off this way from the water. More importantly, heat is extracted from the air as the boiling point liquid water grabs the needed energy for its freedom into gas.

In thermodynamic terms, the two driving forces in the universe are a simultaneous tendency for less enthalpy and more entropy. Tending to less enthalpy is to cool down and dissipate heat. Tending to more entropy is to become random and free. Personally, I strive for less tension and more freedom, although sometimes I must compromise one for the other. And that is what water is doing in an evaporative cooler. The quest for freedom on a molecular level is one of the two guiding forces in its physical existence. To gain the greater measure of entropy, it is willing to sacrifice a little enthalpy.

[JohnZ]

I'm dating myself, but I still remember all the "swamp coolers" all our Army buildings had in Fort Wolters, Texas (Army Helicopter School) in the early 60's; they did reduce the temperature somewhat, but loaded the air with humidity so you sweated anyway, and mold/corrosion was a constant issue.

A little Friday A/C humor - you can hear this guy saying, "$1,600.00 to fix my car's A/C? Are you nuts? I can fix it myself for LOTS less than that!"