When it’s warm but not hot enough to spend energy running an air conditioner, a window fan can help you circulate hot air out of your home or cool air into it. To do so with ease, most window fans operate in either direction with the simple turn of a switch. They are often particularly useful in the evening when the outside temperature has dropped while it’s still warm inside.

To choose the best window fan for your home, consider the dimensions of your windows. You can find both vertical window fans and horizontal window fans. Some small window fans are also adjustable to work with larger windows if needed.

To move air throughout your home effectively, you may want to use your window exhaust fan in coordination with additional fans, like pedestal fans and tower fans. When you set these up to work together, you’ll be surprised at the cooling you can achieve.

Your fan will need to fit snugly in the window, and if you want to leave it there when you’re out of the house, you need a lock that allows the window to remain partially open while secured. Windows that face a garden or shaded area are the best place for window fans because greenery and shade cool the outside air, so your fan will be circulating cooler air into your home.

If you are concerned that a window fan might bring in pollution or allergens like pollen, you should also use an air purifier in your home. Air purifiers work best when placed near circulating air rather than stagnant air. When choosing the best air purifier for your home, pay attention to filtration type and any additionally features you may want, like heating or cooling.

For particularly humid climates, increase your comfort with a dehumidifier. Meanwhile, for dry ones, you will benefit from an evaporative cooler.