Everyone seems to have their own point of view on this. Some agree, others vehemently disagree. Some manufacturers give you the go-ahead, and others say yes, but give you a list of warnings. The internet is loaded with conflicting information. Who is right, who is wrong? Should you run an air conditioner & ceiling fan together? Let’s answer that.
You can— and should— run your ceiling fan and A/C together. Using both at the same time is a more efficient way to cool a room and will ultimately result in energy savings. But you can’t just walk into your home and turn the on. You have to do it right. Otherwise your electricity bills will shock you-literally.
How you can use a ceiling fan and A/C together
It’s simple really:
Why 4°F? Firstly, because it has been proven to work. Secondly, because the U.S Department of energy has recommended it, saying that you can raise the setting by that temperature range without any reduction in comfort. This means that if your thermostat setting is kept at 75°F, and you turn on the ceiling fan, you should bring up the A/C to 79°F. Of course, you don’t have to limit yourself to exactly 4°F – pick what’s most suitable for your case. The AC will keep you cool, but at a lower cost. How’s that possible?
How the ceiling fan and A/C work together
A small portable AC unit can lower the temperature of your home by cooling the air. The ceiling fan gives you a wind chill. A wind chill is that effect you get when you’re out in a breeze. Air moves across you skin, disperses heat, some sweat evaporates, and you feel cooler. When the air conditioner is running, the ceiling fan circulates cooled air and makes you feel even cooler. That way, the thermostat can be displaying 80°F, but you feel up to 5°F cooler due to that wind chill. This will allow you to crank up your thermostat, save on power, and feel cool all at the same time. It also reduces the carbon footprint of your house, which is a welcome bonus.
Ceiling fans circulate the air inside a room. They don’t get outside air into the room or push internal air out. They work by blowing air downwards and removing any hot air around the objects below it. To be clear- a ceiling fan does not cool the air. Cooling is the work of the A/C. The fan just moves the air around. This helps heat leave you and get into the air, providing that cooling effect you desire. However, there are whole-house fans in the market that can get air from outside into the house. And when you leave the windows and doors open, the ceiling fan can actually pull air from outside in. Only do this if the air outside is cooler. In such cases, the fan does some of the cooling.
What about the costs?
Let’s assume your central air conditioning runs about 5 kilowatts and costs you about 40 cents/hour. Let’s put your ceiling fan at 5 watts, costing 2 cents an hour. When you run both at the same time, less power is spent by the A/C. That means you’ll be saving on your utility bills. Most households get an average 8% reduction in A/C electrical use for each degree that they raise the A/C. Modern ceiling fans are very efficient. For instance, in the US they cost around 16 cents a day to run. You spend less when you keep both running. Your total cost savings depend on how much you use the two appliances together.