Myth or Fact: Does running a ceiling fan help to keep the room cooler?

It is a common misconception that ceiling fans help the room to be cooler. It indeed gives a cold feeling but the reality is it simply moves the air around your home. Ceiling fans are commonly used together with the air conditioner to have a cooler effect.

Indeed, homeowners utilize ceiling fans due to their better cooling experience. Here are some things about ceiling fans that a lot of people seem not to know.

Ceiling fans heat the room

Yes, a ceiling fan is a cooling device.  (See number 2 below.)  But its effect on the room it’s in is to add heat.  Why?  Because electric motors are devices that turn electrical energy into mechanical energy, most of which end up as heat.

Ceiling fans cool people

Ceiling fans are useful for cooling only when they move air over skin.  They cool our bodies two ways:  by aiding evaporative cooling and by aiding convective cooling.  If the air movement created by a ceiling fan isn’t hitting anyone’s skin, it’s just making the space warmer with no cooling benefit.

Bigger is better with ceiling fans

While you’re checking those labels, you may notice a correlation.  The fans with the longest blades have the highest efficacies and those with the shortest blades have the lowest.

Lower speeds are more efficient

Another thing you’ll notice when looking at fan efficacy labels is that you’ll get more cfm per watt when you run the fan on medium than on high and more still on low than on medium.  The only logical conclusion here is to get the biggest fan you can fit into the room, leaving proper clearances, and run it on the lowest speed that keeps you comfortable.

Ceiling fans probably won’t save you any money if you have air conditioning

Once you have a house with air conditioning, though, the dynamics change.  That air moving over your skin still feels good, and so does the low temperature, low humidity air produced by the air conditioner.