Garage Insulation / AC recommendations

YellowJacket RV9 · #1 06-06-2013, 05:34 PM

I have come to the conclusion that I will be much more productive, and have an easier time recruiting help, if I can somehow keep my garage a bit more comfortable during the Florida summers. I am wondering if anybody has experience insulating and cooling a standard 2-car garage. Planning on installing a Home Depot garage door insulation kit, and then using a portable AC unit. Any recommendations on BTU's, etc?

DonFromTX · #2 06-06-2013, 07:01 PM

I just finished building on a 26 by 26 ft two car garage for building airplanes. I insulated the doors with styrofoam sheets cut to fit, give a bit better door insulation.
I bought the largest 120v Lowes had, a Frigidaire 12100 btu unit, remote controlled. It does a plenty fine job of keeping it cool and is very energy efficient..

David Paule · #3 06-06-2013, 07:07 PM

My garage doesn't have a ceiling, so it was pretty easy to make the decision to have the inside of the roof and the gables (I think that's the word) sprayed with foam. They put in 6" and the result is fantastic. Recommended, along with wall insulation.

At the time, three or four years ago, the price was $200 plus $.85 a board foot for the foam. That included the fire-resistant paint.

Dave

Kyle Boatright · #4 06-06-2013, 08:00 PM

My HVAC closet was off of the garage, so i just cut a vent into the plenum and opened that vent to heat or cool the garage as necessary.

I also did a reasonable amount of insulating of my garage.

IMO, the key isn't to make the shop a 75F environment. It is to prevent it from becoming a 95F, 90% humidity environment.

jlfernan · #5 06-06-2013, 08:32 PM

I've got one of these and it works great in my two car garage.

http://www.amazon.com/Haier-CPN14XC9...portable+14000

Wayne Gillispie · #6 06-06-2013, 11:17 PM

I would recommend disconnecting the opener, sealing off one door completely then applying several inches of insulation over inside of door. Apply tinting to any windows. Check for 12" min insulation in attic with plenty of ventilation. Seal all openings around electrical junction or switch boxes. Use LED or fluorescent lights. Insulate hot water heater if it is in your garage. Install air compressor outside. Install 12-15,000 Btu A/C up high on the shadiest side for better efficiency. Enjoy.

MarkW · #7 06-07-2013, 07:46 AM

Chris,
Since you are in Florida your biggest heat gain will be the sun. In order of importance:
Insulate the ceiling if it is attic above. The radiant heat from the ceiling will be killer.
Only bother with the door insulation if it faces the sun while you are in the garage. East morning or West afternoon. Mine faces North and insulation would not be worth it.
As Wayne says protect any windows. I have mini blinds on the East window.
A small portable will help alot but probably not 75 degrees. Mostly you want to get some humidity out.
I installed a Hybrid/heat pump hot water heater to save money on hot water and the by-product is a little bit of A/C in the garage. All the other ideas are good but afterall it is a garage.

cfiidon · #8 06-07-2013, 08:11 AM

I cooled my motor home shop (20x50x16) with a 2 ton window unit. Without insulating the doors, it would get as high as 90 inside, BUT... Only about 20% humidity. Tolerable with a little air moving around. An aluminum foil barrier on the large roll up doors would have helped, but I just never got around to it. If I was working in the airflow from the ac it would get too chilly sometimes.

I turned the ac on early in the am...off at the end of my work day. I estimate it cost me 50/month in electricity for 6 months of the year.

Don

Gisnar · #9 06-07-2013, 09:22 AM

I insulated my garage door with thermax ( foam base), used floor adhesive to stick it on. Also be sure to seal around the base of the door. Also insulate the walls and roof.
Be sure to use some sort of fire suppression, ie gyp board. Most of the foam insulations are flammable and you do not want to lose your house.
Also think about wiring both 110v and 220v around the walls as well as lighting at the same time.
Last, do it to code. The codes are there for a reason and will protect you at resale and if you ever have an insurance claim.
Probably more than you wanted to hear.

mikehoover · #10 06-07-2013, 10:00 AM

I put a Frigidaire 25000 BTU window unit in my 24x36 metal pole building workshop that has 2" insulation in the walls and roof and 1" foam board insulation installed in the two metal garage doors. That air condition will keep it 72 degrees on any day of the summer here in SC where we have some pretty severe heat waves.