This spring, we were delighted as kittens in a perpetual sunbeam to have, well, a perpetual sunbeam coming in through the glass doors to our balcony. We were on the third floor of an old brick building that still had winter’s cold in its bones. However, when summer arrived in all of its glory, the temperature in our unit spiked to the high 90F/30Cs. And this was all because of our big glass doors turning our humble abode into a greenhouse.

So we sweat a lot, we stood in front of fans, and we even broke down and turned on the AC for a couple of hours, just to bring the house back to 85F/29C. Then, on a camping trip, a friend suggested putting foil up. Of course, foil! What a brilliant idea!

Super lightweight foil emergency blankets cost about $1.50 at outdoor gear shops

Super lightweight foil emergency blankets cost about $1.50 at outdoor gear shops

As soon as I got home, instead of diving into the roll of Reynold’s Wrap, I dug in our camping box and pulled out the two foil emergency blankets that had been living there, unused and nearly forgotten, for about 7 years. I pinned them up to the outside of our balcony curtains, and Voila! The curtains became impenetrable to the sun light, and therefore the heat. The greenhouse effect was neatly thwarted.

Left panel: before; Right panel: after

Left panel: without the foil blanket   |   Right panel: with the foil blanket

So how well did it work? Before the foil curtains, though we had been using box fans to move night & day air around, our thermostat was reading in the 90F/30Cs. After the foil curtains, our thermostat was reading in the 80F/20Cs.

But most importantly, repurposing the otherwise unused foil curtains that we already had made the difference between us being too hot and being comfortable — without having to turn on our AC. And even if we bought new emergency blankets (2 blankets x $1.50 at outdoor gear stores), we’d have invested only $3 on this fix and still prevented a lot of unnecessary electricity usage.

What methods do you use to keep your house cool in the hot months?