Figured out after 3 summers that I've been insulating my desert house all wrong

I was out in Phoenix last August trying to keep my house under 80 degrees during a 115 day. My electric bill hit $380 and I was losing it. Then a friend who does energy audits came over and pointed out my attic insulation was basically useless because I had it crammed against the roof deck instead of the attic floor. He said all that heat was just baking into my living space through the ceiling. I had no clue I was supposed to leave an air gap and use radiant barriers in this climate. Now I'm ripping it all out and starting over next weekend. Has anyone dealt with retrofitting a 1980s tract home for desert heat or am I the only one who missed this?

3 comments

3 Comments

linda_reed13d agoMost Upvoted

Oh man, I feel your pain! I did the exact same thing with my garage last year and wondered why it felt like an oven in there no matter what I did. My neighbor finally told me about the radiant barrier thing and I felt like such a dummy for not knowing sooner. I ended up using that foil faced bubble wrap stuff stapled to the rafters and it dropped the temp by like 10 degrees easy. The whole attic floor insulation thing is a game changer too, I stuffed mine with R-30 batts and actually sealed all the gaps around the light fixtures with caulk, which helped a ton. You're not alone on this one, these old houses were built like crap for the heat.

lewis.brian13d ago

@linda_reed wait, you sealed the light fixtures with caulk? that sounds sketchy af, doesn't that get hella hot?

the_alice13d ago

Stapling bubble wrap to the rafters dropped the temp by 10 degrees" sure, if you want to believe that. I've seen those DIY radiant barrier jobs and they usually sag and collect dust in six months, making them basically useless. Maybe just check if your AC unit is actually sized right before you go crazy with the foil and caulk.