Q.  I live in an old 1920s apartment with great light and a southern exposure. Because of its age, the insulation has all rotted out, so the thick plaster walls heat up during the day and hold that heat. To try to take advantage of the cool night air, I open the windows after sundown and keep the windows and blinds closed during the day. We don’t want to put in an air conditioner, and obviously we can’t install new insulation. Is this the most effective way to deal with the heat?

Mike C.
Long Beach, CA

A. Dearest Mike,

The ‘20s were a time of jazz, booze, social liberation, and, apparently, emotionally charged gatherings in miserably hot rooms — one need only look to The Great Gatsby’s Plaza Hotel scene for proof. So while your experience may not be comfortable, at least it is historically accurate.

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But that’s cold comfort (so to speak) on a hot summer’s night, Mike. You’re certainly doing yourself a favor by buttoning up the house during the day and opening the windows at night: This classic strategy keeps out the sun’s radiation when it’s hottest and lets in the evening’s cooler air. Still, there’s more you can do to survive a heat wave in a vintage apartment, no energy-intensive air conditioning required.

You’re on the right track with your sunny windows – 30 percent or more of your home’s heat enters this way. You can further foil the furnace effect by shading them with awnings, which the Department of Energy says slash solar heat gain by up to 65 percent on south-facing windows. You’ll probably need your landlord’s support to install anything permanent, but it’s certainly worth asking. No go? Can you make your own portable shade with a patio umbrella, large potted plants, or a tie-on sun shade? If they’re appropriate for your climate and your windows (not to mention your landlord), you might also get some good use out of reflective window films.

Now that you’ve shaded the outside, let’s turn our attention to the inside. Blinds are quite effective at blocking heat transfer (by up to 45 percent, says our data-loving DOE), and they allow a bit more control for letting in light. But dual shades might work even better for you. The light-colored, highly reflective side faces out, and the dark, heat-absorbing side faces in to fend off even more rays (flip them in winter for the opposite effect). To further boost effectiveness, make sure the drapes reach to the ceiling — then seal the bottom and sides with Velcro or tape to lock heat in, like an apartment-sized sous vide.

And if you’re not using them already, Mike, definitely deploy a few fans. If you have ceiling fans, make sure they’re blowing air down, not up, for maximum cooling. I’m also a big, uh, fan of blade-assisted cross breezes: If your layout allows, place one box fan in the window where you get the most wind, facing inward to pull that fresh air inside. Place another fan in a window across the apartment, facing outward, so that it blows stale air out. This method can be quite cooling, particularly if you have Pacific Ocean breezes to play with.

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Here’s another nifty fan trick I learned from Gatsby and co., among other sources: Pile some ice cubes in a pan or bowl (big enough to contain all the water when it melts) and plop it in front of a fan – voila, an even more refreshing breeze! And it’s California drought-approved, as you can refreeze the water for your next steamy night.

Beyond the classic moves we’ve just discussed, there are all kinds of other methods for keeping your cool. Avoid using heat-generating appliances, such as ovens, hair dryers, even computers and TVs, when it’s really cooking outside. Hang a wet sheet in front of an open window, or over your body in bed, or wear wet pajamas. Go to bed with a frozen water bottle. Find still more tips here. And let’s all remember that this sultry season has its charms, too, and indulge in swimming pools, watermelon, and a margarita or two while the sun shines.



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