How Windows Keep Your Home Cool During the Summer

In the depths of winter, of course, a weeklong heat wave with temps above 80 degrees sounds delicious. When high summer comes around, though, we’re left, sun-stunned, dreaming of those frigid January days, those November windstorms–anything but the tropical swelter we’re just barely enduring. Ah, the joys of weather in the American Heartland…

Some bite the bullet and spring for home air-conditioning to combat the torrid months, but one of your great allies this time of year is rather more fundamental: your windows. Falling into the routine of strategically opening and closing your home’s windows gives you some remarkable finesse in managing the heat inside.

Making Windows Work for You

In a house that’s decently insulated, the basic strategy is this: open your windows in the evening, and keep them open through to morning. You want to close them when the outside temperature’s hotter than the inside, which obviously varies based on weather conditions. Very roughly, you’ll probably be shutting those windows and drawing the blinds by mid- or late morning. Sealing and shading the house during the broil of midday and afternoon preserves to a great extent the cool air drawn inside at night.

It can feel counterintuitive–heck, even a little depressing–to close windows, shutters, and blinds on a blazingly sunny day, but the alternative can be miserable. Even if there’s a breeze blowing–making the air beside a windward open window feel nice and refreshing–you’re welcoming heaps of steamy air in by leaving windows open during the hot stretch of the day. Then again, sometimes you can use a breeze to your advantage, as this Rodale’s Organic Life article explains.

Some people even use indoor and outdoor thermometers to more precisely time the opening and closing of their windows. If nothing else, it’s worth doing for at least a week or two to gauge an empirical mercury reading against your unscientific “feel”: You may find your own subjective sense of the temperature difference substantially off–i.e., it may be several degrees warmer outside than in even when your skin’s registering the opposite, especially if there’s a misleading breeze muddying the picture.

Assessing Your Windows’ Condition

Of course, using this method to stay cool in the summer depends on windows that are in good working order. An off-kilter or degraded window may not do an adequate job sealing out that sultry afternoon heat; furthermore, such a window may not be able to long handle the daily “workout” of opening and closing. Before summer hits in full force, inspect your home and install replacement windows where necessary. This’ll obviously serve you well on the other end of the calendar, too, when it’s downright icy outside.

Be savvy with your windows, and you can keep your house surprisingly cool and comfortable all summer long without the expense of installing air-conditioning–or save money by only using the A/C when a really monstrous heat wave sets in, and otherwise relying on the open-and-shut approach.