Keep Your Home Cooler By Selecting The Best Windows To Open

Keep Your Home Cooler By Selecting The Best Windows To Open

Don’t let the summer heat get you down. A smart strategy for using your windows can help you stay cooler when it’s at least comfortable enough to crack open a window.

Photo by Dave Hopton

One familiar trick is to cover an open window with a damp sheet. Hot air that comes in through the sheet will evaporate the water and create a cooler breeze. CBC News says you can take this “swamp cooler” (or evaporative cooler) a step further if you are in a multi-story dwelling:

Open windows on the top floor that have the most sun exposure, and open bottom story windows with the least exposure, then place the sheet over the coolest window.

“The upper floor of your house is going to be hotter than the lower floors because hot air rises. So opening windows at the top and opening the windows at the bottom will create a chimney effect — cool air being sucked in and hot air leaving through the top floor,” says [James Drummond, professor of atmospheric science at Dalhousie University in Halifax].

“The sheet may simply add to the cooling effect of the air stream,” he says.

The article notes that this unfortunately doesn’t work well when it’s very humid out, because the humidity reduces the evaporation and, thus, cooling effect.

However, Lifehacker reader timgray suggests opening windows both upstairs and downstairs can still be effective, because of that chimney effect. And if you live on one floor:

Open the top and bottom of your windows. Most windows will allow the top sash to open typically for this exact reason. […] Venting from the top near the ceiling and letting in cooler from below takes advantage of convection.

Yay, physics!

6 cool, quirky ways to weather the heat [CBC News]


  • This idea of hanging up a damp sheet works well in low humidity environments but not so well in high humidity. All is does it add more moisture to an already humid atmosphere. Its great somewhere like Perth WA where I used to live but not too good in Brisbane where I am now.

  • Swamps coolers- great for arid areas [Alice Springs] not so great for humid areas [Darwin in wet season].
    Hands up those who have windows that open top and bottom? Most new house designs have windows that slide from side to side: less effort to open.

      • Yeah, like I said – great for arid [dry] areas. Here in Adelaide, they’re still pretty good unless there’s a summer storm, then you have about 2 to 3 days of humidity with zero cooling.

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