I am located in Houston, TX and so you can imagine how hot and humid it is right now in the summer. I live in a 3 story townhome style house with an attached garage. And another thing is that I also charge my Tesla in the garage and so in the summer, it gets quite hot in the garage.

So trying to cool down the garage, I'm wondering if it would be better to add a couple ventilation grills on the garage door instead of adding insulation foams on the door?

Maybe I should do both? and have a cutout for the ventilation on the insulation. What do you all think?

  • 1
    What is the inside temperature and outside temperature of the garage? Jul 14, 2023 at 19:35
  • What are the materials the garage is made of, what are the dimensions? Dec 13, 2023 at 1:52

2 Answers 2


As for the insulation question.

Use infrared thermometer and measure the wall temperature outside and inside.

The result will not only tell you if you need insulation but give you direction how much R-value you should use.

For example, if the Delta is small, your current insulation is not doing much. It should be at least 20 F delta.

You need 3 numbers.

The outside Air Temp.

The outside wall temp exposed to Sun

The inside wall temp on the opposite side of the Sun wall

You do not need infrared to measure human temp unless you want to.


Ventilation is always good, but know you will not lover the temp below outside air temp. So it is not a OR question, it is AND.


The most significant change I've made was to add Reflectix as an air barrier on my garage door. Doing that dropped temps nearly 15 degrees, even more, due to it facing the sun during the day. Outside of that, you can also look at insulating the walls that don't contact the home as they are usually uninsulated. Home stores rent blown-in insulation machines and bats to blow into the uninsulated cavities in the wall and ceilings via holes that can be easily patched up after the work is done. You can try foam for appearances but the differences between the two are vast, you can see some testing from many DIY install videos on youtube. In short Reflectix rolls are at home stores such as Home Depot & Lowes, then measure the spaces on your door, and using work gloves, cut the sheets to size for a snug fit inside each door panel and you should be amazed at the difference.

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