How to Use Fans to Cool a Room

Fan in Window

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Using a fan is a simple, inexpensive way to cool a room, especially when compared to the high costs and environmental impact of running an AC.

A portable or ceiling fan costs 50 times less to run than central air conditioning, plus no harmful refrigerant is required. Even if you do use ACs, fans can lower their overall cost by supplementing their operation or reducing the frequency of their use.

Create a Fan Cross-Breeze With Two Fans

Move cool air into the house and hot air out simultaneously by creating a cross breeze. You'll need two fans and two windows that open.

  1. Position one fan at an open window so that it's blowing into the room.
  2. On the opposite side of the house, find another window that's in a straight line from the first window.
  3. Clear obstructions between the two windows (chairs, tables, etc.)
  4. Open the second window.
  5. Position the other fan near the second window so that the air is blowing out of the house.
  6. Turn on both fans.

Create a Cross Breeze With One Fan

Even if you don't have two fans available, one fan can still create enough of a cross breeze to push out some of the hot air.

  1. Open one window.
  2. Tightly close all other windows near the open window.
  3. Locate a second window on the other side of the home, in a straight line from the first window.
  4. Remove obstructions between the windows.
  5. Open the second window.
  6. Turn on the fan.

Draw in Cool Air, Expel Hot Air

You can cool a room with just one window and one fan. Place a box fan in the window or a pedestal fan within 5 feet of the window. When the air is cooler outside than it is inside, point the air so it blows into the house.

When the two temperature points reverse and it's warmer indoors than outdoors, turn the fan around so the air is blowing toward the outside.

Properly Size Your Ceiling Fan

If the ceiling fan isn't cooling the room, it might be because the fan isn't the correct size. Install a ceiling fan that's large enough for the room. Larger fan blades move more air for only a fractionally greater power draw.

Room Size, Square Feet Blade Size, Linear inches
 50 or less  29 or less
 50 to 75  29 to 36
 75 to 175  42 to 48
 175 to 350  52 to 56
 350 or more  60 or more

Change Ceiling Fan Rotation Direction

Cold air sinks and hot air rises. During hot spells, you'll want to bring up that layer of cooler air and force the top layer of heat to stay in place. You can do this with your ceiling fan. Make sure that the ceiling fan is turning counter-clockwise to draw up that cooler air.


While you're at it, make sure that the ceiling fan is balanced; that it's spinning quietly; and that the pull chain is in place.

Combine Fans With AC

Fans can boost your AC's ability to cool your home. In fact, a ceiling fan allows you to raise your AC thermostat by 4 °F and still maintain the same level of comfort. Box, oscillating, or pedestal fans positioned near AC air registers help broadcast the cool air over a greater distance.

  • Do fans cool a room?

    Technically, fans do not cool a room. Instead, they cool people in the room. Fans create airflow and the illusion of a cooler room. Fans do not lower body temperature nor do they prevent heat-related conditions like heat stroke, heat cramps, or heat exhaustion.

  • When are fans not effective against heat?

    Fans are good only up to a certain indoor temperature point, usually agreed to be about 95 °F. As long as the outdoor temperature is less than the indoor temperature, a fan is effective and will cool down indoor heat. The fan must be blowing from the outside to the inside. When the indoor temperature exceeds 95 °F, fans can actually work against you, causing your body to gain heat.

  • Which is more efficient: ceiling fan or portable fan?

    A ceiling fan is more efficient than a portable fan, moving more air at less cost. A 20-inch box fan on high will move 1,820 CFM (cubic feet per minute) and draw 83 watts. A 52-inch, four-blade ceiling fan on high is rated at 6,190 CFM and draws 50 watts.

Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Air Conditioning.

  2. Conservation Tips. Connecticut State Office of Consumer Counsel
  3. Fans For Cooling.

  4. Extreme Heat.

  5. When It's Too Hot For a Fan. New York Department of Health