garage gets too hot during summer months

Old 05-03-10, 08:25 PM
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Location: San Jose, CA
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Question garage gets too hot during summer months

I'm looking for the most cost-effective ideas to help my garage from trapping so much heat during the summer months. (I'm in San Jose, CA.)

My garage is roughly 20' wide, 20' deep, and my walls are 9.5' high. I have a total of 8 soffit vents that are 14"x5", and 1 gable vent that is 2'x1'. One side of the garage is actually my kitchen wall, so I'm guessing a lot of the heat from my garage gets transferred to the living space during the evening.

Apologies for the odd angles, but here are some pics:
garage pictures

I have very limited knowledge about this stuff, but based on my google research, I read that solar-powered attic fans don't really move a whole lot of air. Some seem to suggest that turbine vents seem to be a good alternative. I'm not too concerned about the aesthetic factor if I can have them installed on the rear-facing side of the roof. However, I am concerned about how much rain gets through because I store lots of stuff in the attic space. What are your thoughts about turbine vents? What size and how many should I have installed?

I did notice that my garage door soaks up quite a bit of heat, but also remember seeing that replacement garage doors are quite expensive.

Thanks in advance for any feedback you can provide.
Old 05-04-10, 08:58 AM
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I see that the ceiling of your garage is already opened to the attic for ventilation. The only thing I would suggest is insulating the garage. If your attic is 140f in the summer it would help prevent that heat from radiating downward and insulating the walls would help if the sun is beating down on the wall.

The walls and ceilings of my garages are insulated and in the summer I remove the scutty hole cover so the heat from the cars can rise up and out. Opening the scutty helps but during the summer there is no denying that it is hot and pulling in two hot cars and shutting the door just turns it into an oven.

I have not found a magic cure other than air conditioning. I use a flexible curtain and a portable air conditioner whenever I need to work in one of the hotter garages. The curtain blocks off the unused areas so I'm only cooling what is absolutely necessary but I still have the get the AC going an hour before I want to work.
Old 05-06-10, 05:37 PM
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If all you have is gable vents, I'd do a ridge vent if you have a long horizontal ridge...which looks like what you have. Another thing I'd do is radiant barrier in your attic. Works great. Your other venting option is getting a powered fan on roof. Make sure you increase soffit venting if inadequate.

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