How many of you have put AC's in the garage? If you've done this, is it best to put a window type unit in or to steal from the rest of the house by cutting a vent in? Seems it would improve ventilation and reduce humidity; might be better for the car, especially here in south Florida.

 

Would taking a cool car out of an A/C'd garage into the heat cause condensation to form in sealed areas that should be moisture-free?

 

Your house A/C probably couldn't handle the added aprx. 3800 cu.ft. of space, most units are designed for a narrow margin of effectiveness. If you add that much space you would be overworking it , could even cause it to fail. A separate window (thru the wall) unit would make more sense but even then your utility costs are going to go way up. Even the separate unit has some problems, some Home Owners Associations and/or city codes don't allow a "visible from the street" A/C window unit

 

After our garage addition, we added a mini-split Trane AC. it is a 2 ton unit that has a head unit mounted to the wall and the condenser outside like a typical home system. The only thing running through the wall is a set of cooling lines and electrical wire to connect the head unit to the condenser. I can take the garage down from 86 to 70 in about 3 hours. If I want to simply keep the humidity low, I set the unit for humidity control and it supposedly keeps it at around 56% humidity.
For reference, our garage is 25x30 with 12' ceilings to accommodate the drive on lift. The unit is very efficient and much quieter than a window unit.
For more info, click on the link below.http://www.trane.com/Residential/Pro...ditioners.aspx
Happy cooling!

 

I have a three car detached garage. I put two fairly big 220V window units in, 18,000 BTU each. I insulated my walls, but not the ceiling (I do have a finished ceiling, but did not insulate above it). And I have metal doors that are not insulated.

I can turn them both on, even in 90+ degrees here in Houston, and in 15 minutes it's pretty comfortable. Today the temperature was about 90 at my house, and I had them on in the morning, then left just one of them running on low fan speed all afternoon. It was downright cool in there all afternoon.

I highly recommend doing this if you live where it is really hot several months of the year. I frequently put my other cars in the driveway late Sunday afternoon, and pull the Corvette and motorcycles in with room to really detail them. You'll really enjoy detailing the car if sweats not dripping all over the car while you work.

BTW, the picture below is of my car turned sideways toward the back of the garage.

 

Thanks. JSchindler, can you repost that pic? Didn't come out.

 

Kerry,

I looked on the Trane page; which one did you get? Outdoor unit? Which?

Thanks.

 

Even if your house HVAC is large enough, you can't just cut in another vent and make it work. You have to have air movement back to your warm/cold air return.

I'm happy with just good insulation of walls, ceiling, and doors. With doors closed stays reasonably cool in summer even with outside 100+, and well above freezing in winter. Heat or cold is not a problem, sunlight is. Garage volume is enough to prevent most humidity problems. Save your utility money and buy yourself mods.

My 1/2 cents worth.

 

As a group we are over the top on this one. Anybody have mequito netting over their cars in the garage?... just curious.

 

There are many reasons why you wouldn't want to tie into your existing system, some of which have been posted already (design capacity of system, lack if return air) but also there are others such as fire safety issues, carbon monoxide dangers, and lack of insulation. You could do a wall mount that is designed for a hotel room of similar footage (a two car garage would be around 500 sq. ft. for example) The issues you will have to deal with are cutting in the opening, including a bearing header that will support the wall loads coming from above. This means repairs to the wall beyond just the area you are going to cut out. You will also need 220V electric and enough amperage capacity at your electric service panel to run the unit. Odds are your garage walls, ceiling and door are not insulated. You will lose quite a bit of efficiency from this. You could rent a insulation blowing machine from a home improvement store and blow the attic above the garage (unless you have a 2-story with liveable above, then you are OK) and you can also cut a small hole in the top of the drywall between each stud and blow the insulation into the wall, filling it up. (assuming there is no mid-span blocking). You can also insulate the existing garage door yourself by using the 2" styrofoam panels they sell at Lowe's or Home Depot.

 

I have a 2.5 ton central system for my 1800 square foot shop. It is almost enough. I've considered adding a couple of Fedders 24,000 BTU wall units ($599 each at MSC) for those times when the central system just doesn't quite cut it, but I'm getting by with a couple of 30 inch fans. Now I like to be cool, and I do a good bit of high amp TIG welding in the shop. Without the welding, the central unit would be plenty.

A central unit is the most efficient way to cool a shop or garage, but those Fedders window units can put out a lot of cold for less money. That's what I would have used if I hadn't stumbled on a used central unit for real cheap.

 

Craig,

It actually requires both. The outside unit actual contains the compressor and condensor. The inside unit contains the evaporator and fan. You can add up to three of the inside units to one outside unit depending on the colling requirements. An hvac contractor can evaluate the space and make a recommendation. This unit makes for a really clean installation and it is so quiet, which is what I really appreciate about it.

The window type ac would certainly work for less $, I am just not a fan of having a window unit hanging from the side of our house. The cost of the unit including installation was $3,500 which for my purposes was well worth the $.

We can discuss more this weekend if you would like.

Enjoy the drive!

 

If S happens and you have a car fire or any fire in the garage. You now have a hole in the sheetrock that will let smoke and fire directly into your house. I would never penetrate that wall. Buy a dehumidifier. Building and fire codes provide a certain level of protection that separates your garage from the house. I would not go there just for a car .

 

In my current 24' x 28' attached garage I installed an 18,000 BTU window unit. Works great, looks OK, takes about 30 minutes to cool a non-insulated garage on a hot day. In my new home, currently under contruction, I am building an additional detached garage which will have its own HVAC system for a cost of $3000. One thing I considered, but chose not to do for aesthetic reasons was installing two PTAC units, like the ones uses in hotels, one in the garage and one in the room over. PTACs heat and cool in one unit and can cost as much as $1000 each. If you choose this option I have found the best prices at www.ajmadison.com. Good luck, Frank

 

Just get a DeHumidifier thats all you need. If you want to work in the Garage get portable "free standing" AC unit that vents to a window with a Clothes Dryer type vent tube. They sell them all over now for $500-$600.

 

I air conditioned my garage with a Fugitsu mini split 2 ton heat pump. The main unit is a wall unit mounted high in my garage that distributes the cool air without duct work. It works great! Most of my cars have frame off restorations and I have noticed no metal rusting due to humidty or moisture.

My garage is an oversized 4 car garage with 3 lifts in it. I live in Florida so attic insulation is a must. I also have a radiant barrier in the attic. Since heat is of no concern the sidewalls are not insulated, but the garage doors are.

I really enjoy being able to work in the garage in the summer and this unit allows me to do so. Highly recommend.

 

I cut a hole in the wall and installed an 18,000 BTU A/C last year. 2 car garage and will maintain 77 degrees on the hottest Florida days. I only use it when working on the car, so as not to sweat into or onto my work. Best garage mod i've done so far.
Bob