Should You Leave a Window Open in the Winter?

August 2024 · 5 minute read

Nights are getting chilly, leaves are falling and days are growing shorter. Winter is just around the corner.

For some of you, that means winterizing your home, making soups and crusty warm breads and tucking in for a long, cold winter. Others laugh in the face of a few snowflakes and a stiff north wind. You like fresh air!

I’m in the latter camp. I’d rather wear mittens indoors than feel claustrophobic and stuffy. Most of the year, you’ll find my windows open, and I wait a long time before turning on my furnace.

But is leaving a window open year round a good idea? I talked to heating, ventilation and air conditioning (HVAC) expert Brad Roberson, president of Aire Serv, and Allen Rathey, director of the Indoor Health Council, to find out.

Benefits of Leaving a Window Open

Great news! There are plenty of benefits to letting fresh air into your home.

Rathey says houses built in the last 50 years are much more airtight than ones built prior to the oil embargoes of the 1970s. That makes newer homes more energy efficient, but there’s a downside: less fresh air exchange. Air that used to vent through drafty windows, doors and attics now simply recirculates through your home.

Throwing open a window to exchange stale air offers several specific benefits:

Should You Leave a Window Open Year-Round?

That depends on your specific circumstances and preferences.

“Leaving a window open year-round is generally not advisable,” Roberson says. “In the winter, it’s usually more energy-efficient to keep windows closed to conserve heat, while in the summer, you might want to open windows to ventilate your home.”

When you open the window, your HVAC unit kicks in make up for the loss of heat or cool air that escapes. That could reduce the energy efficiency of your unit, Roberson says, and raise your energy bill. You may decide the fresh-air benefits outweigh a slight bump in cost, however.

“If you’re trying to improve indoor air quality, control humidity, or simply enjoy the benefits of fresh air, opening a window occasionally may be helpful,” Roberson says.

“The key is to strike a balance, ensuring that it doesn’t lead to excessive heat loss or discomfort. Using a window briefly during milder winter days can help achieve the benefits without causing your HVAC system to work excessively hard.”

Remember, too, your wallet and HVAC aren’t all that take a hit from wasted heat. Fossil fuel consumption directly contributes to climate change. So be judicious.

Leave a Window Open in Winter If…

Person's hand crank opening window in the winter time with ice against the glass windows and snowy backgroundMumemories/Getty Images

Window openers, we’re in the clear, at least some of the time. If it’s a beautiful Texas day and you want some fresh air, turn off your HVAC and enjoy. But in Minnesota, if you’re snuggled under mountains of blankets and want to crack open the window while you sleep? Up to you.

“There is no ‘one-size fits all’ when it comes to our indoor spaces,” Rathey says. Let climate, humidity, air quality and other factors specific to you and your family inform your decision. “You can leave a window open in the winter,” Roberson says, “but it’s important to be selective about when and where.”

Consider leaving a window open…

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