Cooling down the garage

Hi all,

When we built our house, we kept costs low by putting cheap carpeting in the living room and bedrooms, doing our own landscaping, and not insulating the garage.   That was the only way we could afford to build our own home because we couldn't sell our old house, had to rent it out, had to get an home equity loan to avoid a jumbo loan, etc. etc.

However, we did put some energy saving features in the house when building it:  a radiant roof barrier that reflects heat, passive solar windows, and a geothermal heat pump (a 200 foot loop of pipe in the ground that uses the earth to heat and cool).  We love these features and have found that our energy bill is half of the local, smaller, Energy Star house that we finally sold!  And we're still waiting for the next electric bill that will show us how much energy we have saved by putting in the solar panels.

Since we moved in, my attention has been on improving the house, including cooling down the garage.  Since our mojave desert climate consists of regular temperatures over 100 degrees from late June through August, the garage doors face southeast, and the outside wall faces southwest, our garage cooked during these months.  If it was 100 degrees outside, it could also be 100 degrees inside.  It also doesn't help that all the approved home and garage colors in our HOA are dark ones!

For my first attempt at reducing the garage temperature, I had solar screens installed on the 3 square foot diameter windows.  I don't know if they did much good although solar screens are supposed to reduce 75% of the heat (or thereabouts) while still letting in light.

Second, I contracted an insulation company to blow in insulation into the outside walls.  That procedure resulted in about a 5-8 degree heat reduction compared to the outside temperature. One drawback--the garage doesn't cool down as much at night.  One other plus--the garage temperature is very comfortable in the winter.

Third, we planted some trees that will eventually shade the outside wall.  "Eventually" is the key word here, which can be translated into "the trees are still small."  

My last trick, just completed about a month ago, involved painting the garage doors with Hy-Tech insulating ceramic paint.  I found this paint on the internet when I was actually searching for sound insulating paint because--although I love our geothermal heat pump--it is mounted on the garage side of the second bedroom wall and pump noise travels through the wall.  More on that some other time.

Anyway, I bought a bag of Hy-Tech ceramic microspheres to stir into a gallon of flat outdoor paint for only $15--much cheaper than the blown in insulation, I must say.  From the brochure:  "Hy-Tech insulating ceramics are a result of the NASA technology developed to combat the extremely high temperatures that the Space Shuttle experiences during re-entry . . . ."  It is "a ceramic insulating additive, that when mixed with the paint creates a barrier to heat."  


The ceramic microspheres look like talcum powder but are in fact little hollow ceramic balls.  The additive should be stirred into paint that has been poured into a larger container because it expands a bit.  Also, the additive makes the paint thicker so I added about a cup of water to it.  I painted on 2 coats with a roller, which resulted in a suede-like surface.  So far it's holding up well.  The best part of all is that it reduced our garage temperature about 3-5 more degrees.  I tested the heat barrier theory by touching the garage door when the sun was shining on it--and it was extremely hot.  This stuff really works!!