Stay cool! How to chill your house in three easy steps

Physicist Jamie Marshall reveals three strategies for keeping your house cool during a Calgary heat wave.

'It’s a gentle application of science to make lives better'

The forecast is for an all-time Calgary high of 37 C on Friday. (Charlie Riedel/Associated Press)

Judging from the weather forecast, there's going to be a few sweaty nights this week.

In the interest of helping Calgarians get a better night's sleep, The Homestretch's Jenny Howe reached out to an expert in cross breezes: her husband, Jamie Marshall.

Marshall, it turns out, knows of what he speaks. He's got a physics degree, and when it comes to keeping the family's (west-facing) house cool on a hot summer night, he knows exactly which way to point the fan.

"He tells me, everything is physics, babe," Howe said Wednesday. "He has a physics degree, so I guess he knows some stuff."

"It's a gentle application of science to make your lives better," Marshall said, in an interview with host Doug Dirks, before launching into his three-part cross breeze strategy.

How to keep your house cool

5 years ago
Duration 1:55
Beat the heat without AC by following these cool house tips.

Keep the heat out

The first thing to remember, Marshall said, is that the same reasons why houses keep the heat inside in the winter is why you can keep the heat out in the summer.

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"Houses are insulated. They're designed to keep that cold out in winter, but also designed to keep heat out in summer.

"Keep your windows closed during the day, as soon as the temperature gets above the interior temperature.

"Keep your curtains and your blinds drawn.

"That sun that comes in your window, it heats up your house, but also heats up all the things in your house.

"Some of the things in your house like counters and floors, have a really high heat capacity that store heat — and that heat comes back to you at night. Keep your windows and blinds drawn."

Jamie Marshall's three steps for keeping your house cool include keeping the heat out, fans pointed backward, and recirculating cool basement air upstairs. (Jamie Marshall)

Blow it backward

The trick with fans is to maximize cool air and evacuate the hot air, both of which require a little bit of counter-intuitive thinking.

"We have these cool, clear nights. It's 30 degrees during the day, but it's 13 to 15 during the night, so use as much fan power as you can, and exhaust all that hot air out of your house," Marshall said.

And if you think there's a breeze blowing outdoors that might help cool things off indoors, think again.

"Don't blow the air into the house, because that prevents that hot air from getting out. You create high pressure within the house. Use a fan, get that low pressure," he said.

"Put your fan somewhere across the house from the place you want to cool the most which in my case would be the bedroom. I run a fan out of the kitchen window, high speed box fan, and I open one window in the house, and that's the window in the bedroom. It pulls that cool air in there all night, and like I said, we need a blanket at night."

And just to be clear: that means turning the fan backward.

"You turn it pointing out. You're trying to get that hot air out of the house," Marshall said.

Basement fan

One final thing: use the natural cooling abilities of your house, by recirculating the cool basement air upstairs.

"Ten feet down, your house is nine degrees in the summer," Marshall said. "It stores a lot of cool air. Use that fan and flow cool air upstairs."

With files from The Homestretch.