Is It Better To Have a Window Fan Blowing In or Blowing Out?

When you buy a window fan, it’s not always easy to know exactly how to use it.

Is it better to have a window fan blowing in or blowing out?

Window fans can blow air in or out of a room. In cooler seasons or at night, set your window fan to blow cool air into your room. If you want to remove the hot air from your room, set your fan to blow air out of the room. You can also replace contaminated air by switching your fan to exhaust mode.

As you can see, the direction of your window fan is determined by the season, temperature, and what you want to accomplish.

Which Way Should You Point Your Window Fan? (Answered)

Let’s talk about the best ways to position your window fan on hot days, cool days, at night, and during the rain.

Keep in mind that the answers in this section assume that your window fan is attached to an outside-facing window.

Is It Better To Have a Window Fan Blowing In or Blowing Out? (On a Hot Day)

On a hot day, the right setting depends on whether it is hotter inside or outside.

If the room is hotter than the air outside, set the fan to blow out. It pushes hot air out and pulls cooler outdoor air in through other open windows. If it is hotter outside than inside, the US Department of Energy advises keeping windows and exterior doors closed instead.

If you have two window fans, you can create a breeze by positioning one fan to blow out and the other to suck in air. This will create an air exchange through the room.

Is It Better To Have a Window Fan Blowing In or Blowing Out? (On a Cool Day)

On a cooler day, you want your window fan blowing air into your house.

When the fan is blowing air in, it is sucking the cold outdoor air into your room. This can cool the house without air conditioning. It will not cut heating costs, so close the window when the heating is on.

Of course, if you feel like you are freezing, you might want to turn off your fan and close the window (This works best if you have a storm guard window fan).

Is It Better To Have a Window Fan Blowing In or Blowing Out? (At Night)

If you are sleeping at night during the hotter months of the year, keep your window fan blowing in.

When the fan is blowing air in, it will bring the cooler night air into your room and help you to sleep more comfortably.

On a steamy afternoon when it is hotter outside than inside, keep the window closed and use a fan inside the room instead.

Is It Better To Have a Window Fan Blowing In or Blowing Out? (During the Rain)

If you’re using your window fan during a light drizzle, it is best to have it blowing in cooler air and blowing out warmer air.

If your biggest concern is water getting on your fan and coming through your window, turn your fan on exhaust mode.

Exhaust mode may push some drizzle away from the window, but it will not keep the fan dry. Check your fan’s manual first. Holmes, for example, says its window fans resist light rain but should not be run in heavy rain or poor weather.

However, do not use a window fan during a hard rainfall or storm.

Read: Are Window Fans Safe in the Rain?

Is It Better To Have a Window Fan Blowing In or Blowing Out? (Ground Floor)

Generally speaking, if your house has several floors, it is best to turn your ground-floor window fans to intake mode.

When the fan is blowing in, it draws outdoor air in at ground level and pushes it up through the house. This works best when the air outside is cooler than the air inside.

Two other considerations:

• If your basement is very cool, blowing air out of your ground floor window can suck the cool air from the basement up into the rest of your house.
• If you live in a one-story house, set your window fan to the mode of your preference for the current temperature.

Is It Better To Have a Window Fan Blowing In or Blowing Out? (Second Story)

What about the window fans in your upstairs windows?

For multi-level houses with multiple window fans, set your second-floor fans to blow hot air outward.

This is because hot air rises. With this set-up, the hot air will rise up through your house and escape out of your upstairs windows.

On cool evenings this can let you turn the air conditioning off altogether.

What Is The Best Way To Position Your Fan To Cool a Room?

The best way to position your window fan to cool a room depends on a few factors.

Factors such as:

• The weather
• The temperature difference inside and outside your house
• The direction of the wind
• How many window fans you own
• How many levels there are in your house

With that said, a window fan only cools a room when the air outside is cooler than the air inside. Blow hot air out of the warmest rooms and bring cooler air in on the shaded side of the house.

If you can, use two fans at opposite ends of the room or house to create an air exchange that will allow you to cool your room faster and reduce the amount of electricity that you use.

Think of this like the draft created by opening the front and back door on shotgun-style houses.

Essentially, you create a wind tunnel.

If the wind direction changes, you might want to experiment with moving your window fan or fans. The more wind that blows into an inward-facing fan, the more cool air enters your house.

Here is an excellent (and entertaining) video of how different fan positions can change airflow:

How To Get Hot Air Out of a Room With a Fan

To get the hot air out of a room, you’ll need to point your window fan outwards.

When the fan is blowing air out, it will blow the hot air from your room and lower the temperature inside your room.

This method needs somewhere for replacement air to come in. The US Department of Energy suggests closing windows near the fan and opening windows in rooms far from it, ideally near cooler, shaded outdoor areas.

At night, you can leave the doors and windows open for better whole-house circulation.

How To Air Out a Room With a Fan

To air out a room means to increase ventilation in a stuffy or smelly room. Airing out the room gets rid of any foul or unwanted odors.

It also fills the room with fresh air.

If you want to air out a room with a window fan, simply point the fan outwards.

Even better, use two fans on opposite sides of the same room: one in intake mode and the other in exhaust mode.

Does Facing a Fan Out the Window Work?

Yes, facing a fan out of a window works for expelling hot air or replacing tainted air with fresh air.

This can cool down a room and make the space more livable.

However, facing a window fan out of the window doesn’t work that well in cold or extreme weather. The impact of a window fan is also reduced if your house is not well ventilated using the most up-to-date best practices.

Final Thoughts

Here are a few more tips for using window fans in your house.

Stronger window fans will cool down your house faster, and properly fitted window fans will prevent cool air from escaping back outside.

You might also be interested in:

• Is It Safe To Sleep With a Fan in the Window?
• Can Fans Get Clogged?
• 4 Most Common Problems With Bionaire Window Fans

Sources

Energy.gov
CDC.gov
Meteorologist Keith Carson (Video)

Reviewed October 2026. We corrected the advice on hot days, heating costs and rain, in line with US Department of Energy guidance.