Pubilshed June 5, 2009
by: Greg Tillotson
Qualification: Ceiling Fan Expert for over 20 years!
Email comments or questions to: firstname.lastname@example.org
A study published by the California Measurement Advisory Council was done to determine the Ceiling Fan usage habits of California residents in 2002. When asked if they raised their thermostat when they turned on their ceiling fans only 2% reported that they always did. 17% said they did sometimes, 72% said they never do and 6% had no response.
You can read the study for yourself, but it's rather detailed and boring in my opinion:
Experience has taught me that when the words "UP TO" are used in front of any claim, I'd better look for the fine print and read the disclaimer. When an ad for a retail product says "Up To 50% OFF" I can be relatively confident that the item I want is more like 10% OFF...if it is discounted at all.
The same holds true for the statement that "Ceiling fans can save you [up to] 40% on your cooling bills". Although it is quite possible, after reading the survey results above, it is not likely to be realized by most people...except for those who read this entire article which holds the golden keys to unlock these potential savings.
Golden Key #1: "The more you raise your thermostat, the less you will spend on your cooling bills."
Common Mistake: "If you run your ceiling fans and air conditioner at the same time and DO NOT raise your thermostat, you will save nothing. As a matter of fact, you will end up spending more money because you will be adding the cost of operating your ceiling fans onto the cost of running your air conditioner!"
Here is a video that supports this concept, provided by AEP TEXAS - An CO-OP Utililty Company
Ceiling fans can cut your air conditioning costs by creating a wind chill effect. Most people can raise their thermostat in the summer and feel just as comfortable. For every degree you raise the air conditioning thermostat above 78 degrees you can save 3 percent to 5 percent on cooling costs. However you won't save it all if you use a ceiling fan do not raise the air conditioning thermostat or if you leave the fan on when you leave the room. Remember, fans cool people not rooms.
Key to a different door: If you rarely ever use your air conditioning or you simply do not have an air conditioner, then using ceiling fans will not save you any money, although they are a very inexpensive way to make you feel cooler.
Golden Key #2: In order to acheive maximum savings with ceiling fans you need energy efficient ceiling fans with powerful high performance motors capable of moving enough air to keep you comfortable enough to raise your thermostat by about 10 degrees or not use your air conditioner at all. The more powerful and efficient your ceiling fans are, the more you will be able to raise your thermostat without sacrificing too much of your comfort level.
Golden Key #3: You need to turn off your ceiling fans when you are not in the room.
Ceiling fans cool you off by creating a wind chill effect, they do not necessarily change the air temperature (read exceptions below). Therefore, If you are not in the room where the ceiling fan is running, you will not feel the wind chill effect and you will have not cooling benefit, so it makes sense to turn your fan off when you leave the room in order to conserve energy.
Exceptions to Golden Key #3
Ceiling fans can also be used to destratisfy the air. Since hot air rises, the air in a room is usually cooler towards the floor and warmer at the ceiling. Destratisfying the air is often accomplished during the winter in rooms with high ceilings where a ceiling fan is run in reverse to draw the cool air up from the floor and force the warm air down from the ceiling. This helps mix up the air to even out the overall room temperature. The same thing can be accomplished in the summer if you have rooms upstairs that tend to be warmer than those downstairs. If you place a ceiling fan in the stairwell and run it in reverse, it will draw cool air from downstairs to the upstairs.
An additional exception to this rule is that leaving your ceiling fans on throughout the house while windows are open can actually help draw fresh air in from outside, which can help keep your home from being "Stuffy". This also works if the air temperature outside your home is cooler than the air temperature inside...kind of like destratisfying the air between indoors and outdoors. In this case, I am assuming that you are not operating air conditioning because you would not want to have your windows open.
There are other factors to consider when it comes to maximizing the energy savings you get from ceiling fans:
As you can see, there are many factors that need to be considered in order to determine how effective using ceiling fans will be for any given application. Every situation is different. I am confident there are a few engeneers who could perform a heat calc in your home and come up with some type of formula to calculate the estimated annual savings given various scenerios of your usage habbits and local climate, but I think you get the point.
So, the best you can do is simply raise your thermostat and install ceiling fans that move the most air using the least amount of electricity.
Emerson has just introduced a ceiling fan that is over 300% more efficient than other fans. This new fan represents a breakthrough in ceiling fan technology and performance and has the potential to revolutionize the entire ceiling fan industry.
Okay, that sounds contradictory to what everyone else is saying about ceiling fans. And what does that have to do with this new Emerson fan that is supposed to revolutionize the ceiling fan industry. Well, before I can tell you how that will take place, I need to put a rest to some misnomers that are going around regarding how using ceiling fans can save you a boat load of money.
As a ceiling fan retailer, over the years I've run across many ads making the claim that ceiling fans can save up to 40% on your cooling bills. I've even run such ads myself...and to this day, we promote this very idea on our ceiling fan website. Although the statement is true, apparently there is some fine print that needs to be made bolder in order for most consumers to realize such savings.
A study done by the IOU (California Investor Owned Utilities http://www.calmac.org.newpubs.asp/) shows that in most cases the savings are dramatically less and that in some cases they are negative. There are several factors that contribute to the lack of savings achieved, but the most significant being that most consumers simply do not raise the thermostat on their air conditioner enough to make a difference. The first rule of thumb when trying to save money with ceiling fans is to raise your thermostat by 5 or 10 degrees. For maximum savings, you would not use your air conditioner at all.
So what the study found is that not only do some people seem to run their ceiling fans and air conditioner at the same time without lowering the thermostat, they also tend to leave their ceiling fans on all day...even if they are not in the room where the fan(s) are.
Now if you have a home with 5 or 6 ceiling fans in it and you leave them on all the time, you are getting no benefit from those fans and just adding to your energy consumption. If on the other hand, you only use a ceiling fan in the room which you are in and turn your air conditioner off or raise the thermostat by 10 degrees, you can in fact save substantially on your cooling costs.
So, the idea that you can feel just as comfortable in a room with a ceiling fan if you raise your thermostat by 10 degrees is hogwash in many cases. The amount of comfort you are going to get from any ceiling fan is directly proportional to the CFMs that the ceiling fan generates (Cubic Feet of Air moved per Minute) amount of air that the fan in question generates.
US Government EPA Ceiling Fan Website. You can find the spreadsheet on that page. Even more, you will find a picture of the Emerson Eco on that page as well...even though the Government is not allowed to sponsor or promote any particular brand or model.
Study of how people use ceiling fans in California
CA Statewide Investor Utility Ceiling Fan Study
How to Save Energy with Ceiling Fans (video)
AEP TEXAS - An CO-OP Utililty Company