Smarter: Should Your Window Fan Face In or Out?


For the first eight years I lived in New York City, I managed to do the near impossible: I hardly turned my AC on in the summer.

Part of it was practicality. I was barely making enough money in the first few years, and I wanted to keep my electricity costs low. Second and perhaps most importantly, none of my roommates at that time had an AC, and I felt selfish for using one while others languished in the heat.

So I rarely turned on my AC and got inventive instead. One summer, I slept with a tower fan laid out on my bed like a person so it could blast air straight into my face. And during a string of particularly hot days, I once dragged my desk to the entrance of my apartment and worked with my front door propped open because I could feel a breeze coming from the hallway. I wasn’t going to let my neighbors’ confused faces stop me from enjoying it. We all have a past. Mine is just a bit sweatier than yours.

For the past two years, I’ve eased up a bit on my no-AC rule because I realized extreme heat can pose a health risk. On the days when it’s not too hot in the summer, however, I still try to use the AC as infrequently as I can, given that its use accelerates climate change. This means that fans have been a lifeline for me, and if you’ve ever wondered whether you’re utilizing your fans properly, don’t worry, I’ve got you covered. Here are the answers to some common questions about fans and ventilation.

Should a window fan face in or out?
When polled, our social media users who used window fans said they faced theirs inside, but the real answer is a bit more complicated.

You should place outward-facing fans on the warmer side of your home to blow the hot air out and inward-facing fans on the cooler side to draw cool air in, says Barry Jacobs, vice president of product development at Comfort Zone, a home environment product company.

If you live in a multilevel house, the upper floors are likely to be warmer in the summer than the ground floor. You can have fans blowing out of the windows on the upper level to exhaust the warm air trapped there, says Chris Regan, an engineer and CR tester of AC units. And when the outside temperature starts to drop, you can pair that with fans blowing inward in shadier rooms to maximize the airflow in your home.

When is the best time to use a window fan? When is the best time to keep windows closed?
Window fans are most effective at exhausting hot air from your home, so in general, the best time to use them is when the air indoors is hotter or less comfortable than the air outside.

When the temperature outdoors is higher than inside, try closing your windows and shades to prevent hot air from coming in and cooler air from getting out instead of using window fans.

Which direction should a ceiling fan spin in the summer, clockwise or counterclockwise?
The ceiling fan should operate counterclockwise (or blow down) so that you’ll feel a cool breeze standing directly underneath the fan, according to the Department of Energy.

If you’re using air conditioning to cool your home, a ceiling fan can allow you to raise the thermostat setting about 4° F without you feeling too uncomfortable, which helps reduce electricity costs. And when you leave the room, make sure to turn off your ceiling fan to conserve energy.

Are electric fans enough to stay cool in a heat wave?
If your indoor air temperatures are hotter than about 95° F, fans are not effective at cooling you down, according to the New York State Department of Health. To be safe, you should stay in air-conditioned spaces as much as possible from 10 a.m. to 5 p.m., typically the warmest time of the day.


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