Will this regulate temperature in some way, or is this just a waste of energy?
It’s a waste of energy. If anything, the waste heat from the motor will tend to heat up the room.
For what it’s worth, some fans make a lot of noise when they are first started.
This is one reason to leave them on, although energy conservation should probably trump it.
It is probably also more efficient to leave it running than to turn it off for a minute or less.
I have a split level home and I always leave the ceiling fans running when the A/C is on. It keeps the cool air circulated throught the home. Without doing this the lower levels will get too cold and the upper level stays warm and the A/C runs overtime trying to get the upper level cool.
In my experience here in hot as Hades Florida, leaving the fans on will result in a cooler, more even temperature throughout the house than flicking them on and off. It also seems to relieve the strain on the air conditioner; it turns on less frequently this way.
My understanding of ceiling fans is that they move virtually no air outside the room they are in. Therefore, unless your home has a remarkably open floor plan, turning them off when you leave a room is the more energy-saving option. Because a fan does not actually cool the air, it merely promotes better evaporation of sweat by keeping the air moving over your skin, if there is no one in the room, leaving the fan on is just wasting electricity.
The OP said nothing about using a ceiling fan in conjunction with A/C. Why assume we are talking about A/C?
(In any event, a properly designed A/C system should not require the use of ceiling fans to operate properly.)
I’d bet that the break-even point is probably only a few seconds. The starting surge for a fan motor only lasts for a fraction of a second.
Well in our home, adding the fans significantly decreased our electric bill. It seems that it costs far less to run them all the time than it does to have the air conditioner kicking on and off more frequently throughout the day. The thermostat is still set at 74, the unit just doesn’t run as hard or as long.
A, what robby said. Given that, B, I don’t doubt you. If you have ceiling fans on, you can effectively raise the temperature at which your air conditioning is set, because the room will feel cooler to you while you are in it. This can certainly result in savings in electricity, because of course a central air system uses more electricity than a ceiling fan. I do this at home: even though I like it very cool, I program my thermostat to actually raise the temperature at night by several degrees. Why? Because at night, I’m directly under my bedroom ceiling fan; I hardly notice that the house is warmer.
A ceiling fan will generally make things cooler as long as you point it the right way. Most modern ones have a switch (down is usually “blow air down” I believe, which is what you want). Otherwise, you’d need to switch out the rotors to blow air down instead of up.
On some older fans, the attack angle of the blades can be changed to push air up or down without reversing the rotation.
I have an enclosed patio that I use as a year-round greenhouse. I’ve got baseboard electricv heaters in winter, but no AC in summer. The rest of the house has central air, so I leave the door to the patio open most of the time, plus a ceiling fan that is always on. I have the fan set to “reverse,” i.e. sucking the air from below. My primary goal is to provide as close to consistent temperature as possible for the plants.
So, if there’s no AC consideration, the fan is a waste. If you’re not spreading cooler air around, then the air is just churning with no benefit. They’re only efficient at cooling people because they evaporate sweat. Without that, they’re not really doing anything.
While it’s true that they do not lower the temperature of the room, fans use more than evaporation to make you feel cool.
Your body is constantly radiating heat into the air. If the air is still, that warm air stays near your skin. You have a tougher time radiating excess heat when the air in contact with your skin is already warm. A fan moves that warmer air away from your skin and replaces it with room-temperature air. This is why a strong wind makes you feel colder in the winter: the moving air isn’t any colder than the still air, but the moving air removes your insulating air layer faster.
To the OP: agree with most of the posters who say that a lonely fan is a counterproductive fan under normal circumstances. One consideration, however, is if you’ve got an open window, bright sun, and still air, you’ll get greenhouse warming. A ceiling fan might mitigate that slightly.
Great. Thanks, everyone. I’ll be keeping it off.