green-building-curmudgeonheader image
Helpful? 3

Ceiling Fans Are Evil

How can something so simple be good and bad at the same time?

Posted on Jul 16 2013 by Carl Seville, GBA Advisor

I can’t count the number of times I have walked past a neighbor’s home and seen the porch ceiling fans running with no one there to appreciate them. All the fans are doing is wasting electricity and contributing a little heat to the outdoor air. I am tempted (although I have never acted on the impulse) to pull the chains and turn the fans off or leave the neighbors a note.

Now, leaving porch fans on is bad, but nowhere near as bad as doing it indoors, especially in the summer. I am surprised at how few people understand the basic concept of fans — that they make you feel cool due to the movement of air across your skin. The same way a breeze cools you off, a ceiling fan can make you feel cooler, but only if you are close enough to it to feel the air blowing on you. If you can’t feel it, it isn’t doing any good.

What about circulating the air?

When I tell (or maybe more accurately, annoy) people about this concept, many of them tell me that it helps circulate the air around the room and keeps the house more comfortable. Unfortunately, most of them are wrong.

There are very few situations where moving air around a house in the summer like this improves comfort. If there happens to be a big temperature difference between the floor and ceiling due to poor air sealing and insulation, it might be useful to run a fan in reverse in the winter to bring warm air down, but that’s not what most people are doing.

On a related subject, I have been in homes where people are using their ceiling fans in the summer but they are running in reverse, moving air up instead of down. I once changed the fan direction for a friend and to his amazement, he actually felt cooler with the fan blowing towards instead of away from him.

Ceiling fans increase energy use

A 1996 study in Florida determined that using ceiling fans appropriately could allow people to raise the temperature inside by 2°F, resulting in about a 14% annual cooling energy savings.

The same study found that most people do not adjust their thermostats when using ceiling fans, actually increasing their energy use rather than reducing it.

Those fan motors are hot

Most people can understand that running a fan when no one is in the room wastes electricity, but the dirty little secret is how much heat they put out when running.

I always knew this, but I was inspecting some very well built affordable LEEDLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. homes recently, and one of my associates had an infrared camera with him. Scanning walls and ceilings showed that the homes were very well insulated and air sealed, but when the camera caught the running ceiling fan there was a huge hot spot at the motor. The temperature of the motor was far higher than anything else in the room, including windows exposed to direct sunlight.

When the IR image was calibrated, we figured out that the fan motor was running at over 100°F. So not only is the fan not cooling the people who aren’t in the room, it’s also working as a little space heater — just the thing you need for a hot summer day.

There is hope

Now I am not suggesting that we should not use ceiling fans — just that they shouldn’t be on if no one is in the room. If people only use them when necessary and set their thermostat a bit higher, then the extra heat is a small price to pay for the comfort and energy savings.

When selecting a ceiling fan, look at the efficiency of the fan, usually expressed in CFM per watt. The Energy StarLabeling system sponsored by the Environmental Protection Agency and the US Department of Energy for labeling the most energy-efficient products on the market; applies to a wide range of products, from computers and office equipment to refrigerators and air conditioners. website has a list of all labeled ceiling fans in a downloadable Excel spreadsheet that you can sort by efficiency. The most efficient fan on the list is the Haiku by Big Ass Fans.

I managed to get an IR image of one of the company's fans as well, and, lo and behold, the temperature of the fan's motor at high speed is only about 81°F. If (like me) you keep your house in the high 70s to low 80s, a fan motor like this won’t make much of a difference at all.

You don’t need to spend a fortune on a ceiling fan. There are many efficient models that are reasonably priced, and there is no reason to get rid of those that are working just fine. You should, however, only use them when they will keep you cool, and raise your thermostat when you do.


Tags: , , , , ,

Image Credits:

  1. Big Ass Fans

1.
Tue, 07/16/2013 - 09:28

Great article
by Nelson Labbe

Helpful? 1

It's amazing how much more efficient the Big Ass Fans are, but the price tag on those put them in the luxury item category for me.


2.
Tue, 07/16/2013 - 10:25

Occupancy sensor control...
by Dana Dorsett

Helpful? 1

...is arguably the best solution for limiting excess fan power use. This should arguably become a requirement for Energy Star labeling too, but currently isn't. Simple cfm/watt requirements is pretty short sided, given how they are actually used.

There would arguably need to be an override capability for fans in sleeping areas, but the fan spinning away on the empty porch has a simple not-very-expensive technical solution. Integrating the occupancy sensor into the fan itself would be a very convenient feature (I don't know of a manufacturer doing that) but it's neither expensive nor difficult to install separate occupancy sensor control.


3.
Tue, 07/16/2013 - 10:29

Why no built in motion sensors?
by Eric Sandeen

Helpful? 1

Seems like a fan with a built-in motion sensor would fit the bill perfectly. I suppose a sensor on the wall would suffice too.

(I too am dismayed at the price of the Haiku fans; that's just unbelievable).


4.
Wed, 07/17/2013 - 08:06

I happen to be one of those
by Jesse Lizer

Helpful? 1

I happen to be one of those that likes ceiling fans. However in the new house finishing construction, all fans were ES labeled (its an ES 3.0 home). I have light kits on them as well, also ES. It was quite hard to find affordable ES rated fans and light kits. We did end up going with a large 72" helicopter fan for our living space that is a big area with high ceilings. I did look at the Haiku fans for this particular location, but it was about 3x the price of the one we went with. It only uses 32 watts at high speed. (293 CFM/watt).


5.
Wed, 07/17/2013 - 08:14

I like ceiling fans too
by Carl Seville, GBA Advisor

Helpful? 1

I actually have nothing against ceiling fans, just their misuse. I realize that not everyone (including myself) can afford a Haiku fan. The fact that more moderately priced fans produce more heat doesn't bother me very much at all if they are not left on needlessly. It's when they are on with no one around that I find really annoying. It all comes down to behavior. As in most things in green building, you don't need to spend a lot of money to have an efficient building - you just need to do things right both in construction and in operation.


6.
Wed, 07/17/2013 - 13:49

I have a few other problems with Ceiling Fans
by Donald Endsley

Helpful? 1

My problems with them are
#1 They aren't balanced from the factory, and wobbling ceiling fans are annoying (and even slightly dangerous). I am also hardly ever able to really get one well balanced. And yes this is an energy issue. With a balanced fan I don't have the chain clanging against the light globes allowing me to sleep. With a fan I can up the temperature of my house from 76° to 78° and be comfortable. There is absolutely no reason that the factory can't get a pretty close balance then include a dynamic balancer to make up for the slight changes in balance when installed.
#2 The blades are broken on my porch units.


7.
Wed, 07/17/2013 - 16:37

No evidence for ceiling fans in winter?
by Jonathan Beers

Helpful? 1

I've been looking for support for running ceiling fans in reverse in winter for years. Haven't found any. On the contrary, the 1996 Florida study Carl mentions says:

"An environmental chamber study by Consumer Reports showed that the long-reported de-stratification benefits when heating are largely unsubstantiated (Consumer Reports, 1993). Thus, benefits from ceiling fans can only reduce cooling needs and this is completely contingent of sufficient changes in interior comfort to warrant raising of the cooling thermostat."
Source:
https://securedb.fsec.ucf.edu/pub/pub_show_abstract?v_pub_id=4080

Plus two more articles doubting winter use of ceiling fans:
http://www.advancedenergy.org/buildings/knowledge_library/heating_and_co...

http://www.interfaithenergy.com/article2.htm


8.
Wed, 07/17/2013 - 17:46

Winter fan use
by Carl Seville, GBA Advisor

Helpful? 1

Jonathan - Even when I mentioned winter fan use, I hedged my bets on the value of it : "If there happens to be a big temperature difference between the floor and ceiling due to poor air sealing and insulation, it might be useful to run a fan in reverse in the winter to bring warm air down."

In a typical house I don't see much value in winter fan use. With a very high ceiling where there the air at the top is much hotter, it might help bring some of the warm air down, but most people won't benefit from this. I think fans are very much a placebo for many people - when they're on they may think they are cooler, but clearly there isn't much benefit other than for convective cooling.


9.
Wed, 07/17/2013 - 17:54

Thank You
by Miriam Kearney

Helpful? 1

I was (until I read your article) one of those that thought circulating air would help in the summer. I'll be turning off all the fans unless I'm there from now on.


10.
Wed, 07/17/2013 - 18:39

I read this for useful
by Brian Godfrey

Helpful? -1

I read this for useful information, not nonsense and boilerplate. I think saying "ceiling fans are evil" is a dumb thing to say. Just about as dumb as running a ceiling fan on a porch. If you are into the totally high tech green philosophy, where everything is air tight and calculated to the point of ridiculousness, and where technologies can only be approved once someone has written their thesis on it or posted the appropriate line item on their resume', then I just don't know what to say. For everyone else, like those who open windows when it is hot, for example, perhaps the message from combining the article and the comments and my personal experience is that ceiling fans circulate the air. Period. The rest is up to you. Apply intelligence to their operation and you will be rewarded. Apply blanket statements, for or against, and you lose.


11.
Thu, 07/18/2013 - 04:50

Response to Jonathan Beers
by Martin Holladay, GBA Advisor

Helpful? 0

Jonathan,
Thanks for providing links to "articles doubting winter use of ceiling fans."

You forgot one link, however -- to a GBA article that also doubts that there are any benefits to the winter use of ceiling fans: Using Ceiling Fans To Keep Cool Without AC.


12.
Thu, 07/18/2013 - 07:26

Response to Brian
by Carl Seville, GBA Advisor

Helpful? 1

Brian - Saying that Ceiling Fans are Evil is not dumb, it's intended to get reader's attention. Just like my previous posts suggesting that Batt Insulation be outlawed or that we stop insulating altogether. And running a ceiling fan on a porch isn't dumb at all, unless no one is sitting under it. Ceiling fans do circulate air, but that feature doesn't do anything to improve comfort, unless the moving air blows directly on your skin. Lighten up a bit and enjoy the discussion.


13.
Thu, 07/18/2013 - 08:36

Edited Thu, 07/18/2013 - 08:40.

Another doubt about "winter" use
by Derek Roff

Helpful? 1

Has anyone studied the effects on air circulation/de-stratification of running a fan in the so-called "winter" direction? If (and it's a big "if") there is sufficient temperature stratification in a space, that running a ceiling fan for air circulation in a winter heating situation makes sense, should the fan be run in the summer direction or the winter direction?

I've never been able to find a study that compares the amount of air mixing and de-stratification between the winter and summer fan directions. Articles often say or imply, as this article does, that running the fans in the winter direction will bring more warm air down from the ceiling than the summer directions does. However, no evidence is given. It might be that both directions provide the same amount of mixing. It might be that the summer direction is more effective in every season. It might be that the fan direction has different effects at low fan speed than it does at high speed.

Personally, I suspect that the recommendation for running the fans backwards in the winter has no research behind it. While a fast-moving stream of air blowing on a person could make them feel colder even in a heated room, fans on the lowest speed don't produce fast air streams. More than once, I have observed people who believe in the winter use of fans switching the direction switch back and forth, trying to decide which is the desired winter direction. Standing under the fans, they have been unable to decide which direction feels warmer to them.


14.
Thu, 07/18/2013 - 08:46

Unsupported conclusions are evil
by David Nadle

Helpful? 1

The provocative headline definitely lured me in, nice job. The rest of the article, not so much. Temperature is not heat. The tip of a lit cigarette is also hotter than anything else in the room but adds negligible heat. You should measure the waste heat off a ceiling fan if you want to make your case, but that would involve actual effort.

You also left out an important application of ceiling fans, which is their use instead of any air conditioning. A ceiling fan and an open window is a pretty non-evil alternative to air conditioning, even if you leave it on when you're not in the room.


15.
Thu, 07/18/2013 - 08:54

Response to David
by Carl Seville, GBA Advisor

Helpful? 0

Happy that my provocative headline drew you in, sorry that you were not satisfied with what you read. I see your point that the amount of heat at the fan is not necessarily the amount of heat entering the room, however, I stand by my primary point, that if a fan is running and not one is there to feel the air flow, then all it does is waste energy and, eventually it will increase the room temperature as well as waste energy. This post is not meant to be a scientific study of the amount of heat a fan throws off, rather I saw the opportunity to educate people who don't understand how to properly use fans by using a dramatic IR image showing how hot a fan gets. Many readers of GBA understand this concept, but some do not, as the comments above reflect. I have already received comments from non building professionals that they appreciated the advice and will now turn their fans off when not in the room.


16.
Thu, 07/18/2013 - 09:23

Edited Thu, 07/18/2013 - 09:26.

When is a link not a link?
by Derek Roff

Helpful? 0

When it is on the EnergyStar website. Like too many other modern websites, some of the URLs (Universal Resource Locator) on the EnergyStar site fail to be universal, nor do they reliably locate the desired resource. Using the "list of all labeled ceiling fans" link provided in Car's article doesn't necessarily bring the browser to article he was aiming for. I clicked through about 15 tabs and articles on the site, and unsuccessfully used the website's search function, before I found the spreadsheet that Carl references. While most readers may be quicker and sharper-eyed than I am, here are direct links to the spreadsheet, in either PDF or Excel format. Clicking the link below will start the download (depending on browser settings).

PDF: http://downloads.energystar.gov/bi/qplist/ceiling_fan_with_lightkit_prod...
Excel: http://downloads.energystar.gov/bi/qplist/ceiling_fan_with_lightkit_prod...


17.
Thu, 07/18/2013 - 09:52

Response to Carl
by David Nadle

Helpful? 0

There is a scenario where it might make sense to leave a ceiling fan on, as contribution to natural ventilation. A serious article might have considered that.


18.
Thu, 07/18/2013 - 10:01

Edited Thu, 07/18/2013 - 10:03.

Natural ventilation
by Carl Seville, GBA Advisor

Helpful? 0

David - I can't think of any situation where a ceiling fan left on would contribute to a suitable natural ventilation strategy, although there might be one. In almost all cases, a ceiling fan only contributes through convective cooling on a person's skin. I could see using a whole house fan (properly installed with a cover and insulation) for night flushing, or even a window box fan to draw air in and out of a house, but a ceiling fan won't do much if anything to contribute to a whole house ventilation strategy. Sorry that my article wasn't as serious as you would have liked, however it is a serious subject and while I sometimes use humor and a light touch, that does not diminish my belief in building and operating high performance homes.


19.
Thu, 07/18/2013 - 12:39

Haiku
by charles CAMPBELL

Helpful? 0

Gotta say I'm leery of ultra-efficient ceiling fans. A few years ago I bought a couple of the Windward III models, which at that time held the most-efficient crown. Soon they began to hum and buzz and loose speed control.


20.
Thu, 07/18/2013 - 13:02

Ceiling Fans
by Tom Barrett

Helpful? 0

I completely agree, most people don't know how fans work to provide comfort. Fans are to cool you not the house. All of the different types of non-mechanical cooling - floor fans, ceiling fans, whole-house fans, and evap coolers have the same "lack of knowledge" problem.

Evap coolers only work if you open the windows and doors and let the warm moist air out. (I was in a building last weekend that was suffering because someone placed big signs on every door and window "Keep Closed Air Conditioning In Use". Only problem is it was two huge evap coolers providing warm moist air to the closed off space. When I tried to explain to the person in charge that it would work better if the doors and windows were opened they told me I was wrong (after 5 minutes in that space I have to leave).

Whole-house fans weren't intended to run 24/7, but to be cycled on 15 to 20 minute intervals. I've never seen them used that way.

Ceiling fans as explained above only work on you (there is a benefit of using them in the winter to circulate air to keep condensation from accumulating on cold walls and windows to reduce mold growth). Floor and window fans can pull hot air out or push cooler air in or they can just blow on a person to cool them. I have and use all of the above instead of air conditioning. I have a ceiling fan in every room of my house (except the bathroom) and only use them when the room is occupied. I even have a ceiling fan outside on my patio that is a life saver when there is no breeze blowing on a hot summer night. Fan cooling can be quite comfortable and save a load of energy - if you don't use the AC.

I recently had the task of evaluating and ranking measures for a low-income energy program. When I stated in my report that ceiling fans have a negative energy benefit (they don't save energy they actually increase its use) I got shot down by everyone in the program. "We've been installing them for years. They save energy in the summer and winter and our clients love them," was their justification for keeping them in the program. Not only did they not understand the myths surrounding ceiling fan use but were perpetuating them. When I asked what kind of fans did they install, they turned out to be the cheapest on the market with a CFL light-kit, not a highly efficient one, because that was what their program could afford. Granted most low-income households I've been in either don't have AC or don't use it because of the cost and ceiling fans provide a great deal of comfort to the occupants in light of no AC, but they don't save energy if you don't have a choice to turn off or up the AC and use the ceiling fan instead.


21.
Thu, 07/18/2013 - 17:26

The myth of ceiling fans
by Ed Dunn

Helpful? 0

For over 20 years, I have been fighting the myth of ceiling fans. Folks got the word back in the 80's that ceiling fans save energy. Since then, when I design/build a sustainable home, many of my clients have asked to have these things installed in each room. For those that do not believe me, that they are useless and are energy users, not savers, I recommend installing a ceiling box rated for a fan, but not to install it unless they actually feel they need it. To date, only one client has done this, claiming they like moving air on their body. Since I have never installed a forced air system in any home I built, this would be the only reason to install one. I did remind them that they do no good when they are not in the room.


22.
Fri, 07/19/2013 - 09:43

Edited Fri, 07/19/2013 - 10:03.

An Alternative
by mark faultersack

Helpful? 0

Though it doesn't always work, there are many nights in a typical summer where homes can avoid air conditioning the next day: by running box fans or window fans to flush the home with cooler outside air until the next morning. Then the windows and shades should be closed for the next day so the day's heat won't reverse the heat flow. This obviously won't work on nights when it is either still hotter or much more humid outside than inside. But if not, it can save or delay airconditioning use. Yes, a whole house fan can work with this approach also, but most folks don't want to bother with the added expense. The advantage of the fan in the window scenario is that by pointing the fan toward the outside, it will take the heat of it's own energy out with the air stream. If you exhaust out on the highest point of the home, then you can choose which side or room of the house you want to draw the cool air in from. You can avoid pulling air in from a hot west side of the home as an example. It works quite well in homes that have plaster walls that have more thermal mass than drywall.


23.
Sun, 07/21/2013 - 13:17

Edited Sun, 07/21/2013 - 13:18.

They are all too common :(
by Kate LaBore

Helpful? 0

Where I live in central Illinois, EVERYONE has these d--n things. I am a renter, and it is impossible to find a rental space larger than 100sq. ft. without a ceiling fan in it. I hate them from an aesthetic point of view, and now I know they are as useless as they are ugly.

However, I would love it if you would explain the following: "A 1996 study in Florida determined that using ceiling fans appropriately could allow people to raise the temperature inside by 2°F, resulting in about a 14% annual cooling energy savings."

Huh? How does raising the temperature result in a cooling energy savings? This begs explanation.

Also, the next paragraph states: "The same study found that most people do not adjust their thermostats when using ceiling fans, actually increasing their energy use rather than reducing it."

It would be very helpful to point us to some guidelines for how you should adjust your thermostat. Is it just a simple matter of bumping up the target temperature a couple of degrees? I am guessing that this means, "you're feeling cooler due to the fan's air movement, so you can actually be just as comfortable in a room that's a degree or two warmer." If this is correct, then it wouldn't save me much, since I already set my thermostat rather high (in most people's estimation) during hot weather. I am fine in a room that's 80-82 degrees, though I notice most other people prefer temperatures below 80. It would, however, keep me more comfortable in such a room (theoretically). I'll find out: August 6 I am moving to a new building with -- you guessed it -- ceiling fans (in every room).


24.
Sun, 07/21/2013 - 21:34

I disagree with the past several posts
by Curt Kinder

Helpful? 1

There is no doubt in my mind that ceiling fans, operated properly, play a role in energy efficiency. Operating them properly is no mystery - treat them as lights. Smart people turn off lights when not needed / room not occupied. There is no reason smart people can't similarly operate ceiling fans. Occupancy sensors are certainly a viable option.

I firmly believe, as per FSEC, an efficient ceiling fan, operated at low speed, provides just enough air movement to allow for a moderate increase in thermostat setpoint during cooling season. Given that a fan operates at 10-15 Watts in low speed, and a central AC uses about 1000 Watts per ton, the math is firmly in favor of the ceiling fans IF the thermostat setpoint is adjusted upward. We have ceiling fans in nearly every room and they allow cooling setpoints of 77-78, rather than the more typical 75. I convinced my wife to allow one in the kitchen. It helps with both cooking heat, and it provides for air drying dishes after the dishwasher completes a cycle.

Winter operation of ceiling fans is a bit dodgy - the smallest air movement across bare skin is likely to be perceived as a cold draft. The use case of breaking stratification in a tall room, perhaps 12'+ might justify a reversed ceiling fan in winter. of course, the better solution is to avoid such high rooms in private homes in the first place.


25.
Mon, 07/22/2013 - 07:02

Put the fan motor in unconditioned space
by Michael Armstrong

Helpful? 0

Not too difficult in a single-story residence with an accessible attic above. Don't know if there's an off-the-shelf way to seal the shaft from the motor to the fan assembly, but that can't be rocket science. I loved the old factory fans driven by a complex belt drive from a single motor, but that's probably impractical for a residence.


26.
Mon, 07/22/2013 - 07:45

Response to Kate
by Carl Seville, GBA Advisor

Helpful? 0

Kate - thanks for chiming in and asking your questions. Perhaps I was not clear in my post and assumed people know more details than they do about heating, cooling, and comfort. As to your first question "How does raising the temperature result in a cooling energy savings?" If by using a ceiling fan you feel more comfortable in a higher temperature room, and you raise your thermostat setting in the summer, then the energy you save with less air conditioning is more than you would use running your fans. In your case, since you keep the house fairly warm, you would not benefit as much as someone who keeps their house at 74 or 76 degrees. I also keep my house in the low 80's most of the time, dress lightly, and use fans to keep cool before I turn on the AC. If you don't like the sensation of a fan blowing on you then using one does not make much sense - however if it does make you feel cooler, then you could use them sometimes and use your AC even less. Comfort comes from a combination of temperature and relative humidity and it is very subjective - one person may be perfectly comfortable in 80 degrees and 60% RH while another person may feel like they are roasting. I tend to feel cold when the temperature is much below 78 in my house and RH is below 50%.


27.
Mon, 07/22/2013 - 10:08

Unbelievable comments
by ice rabbit

Helpful? 0

Unbelievable comments. Many from people who don't disclose their location / region nor the physical characteristics and energy efficiency of the properties they live in or are building / commenting on etc.

In the cooler parts of the country, you probably don't need ceiling fans, except for when there's a heat wave.

In the warmest parts of the country, ceiling fans are most welcome. They allow you to set the AC thermostat 5 degrees higher or forgo using it altogether, whether at the dining table, office or bedroom. Of course the same can be accomplished with pedestal fans, but those take up floor space, don't distribute the air so evenly, don't have a switch by the door. So, why not take advantage of a central ceiling fan? I've updated and upgraded our ceiling fans, and couldn't be happier. First hand experience in Florida, from someone who is not all that heat tolerant: in the average home, with flat ceilings, using the AC more moderately (higher set temp) combined with using ceiling fans in occupied spaces, saves electricity, reduces peak load, etc.

Does that mean there should be a ceiling fan in every room in every house in every state? Not. At. All.

As for the author ... that ceiling fans raise the temperature. Oh please. So does the fridge in the kitchen. So does the dishwasher, the dryer, the AC unit outside. Lets just toss all out, wear leaves and live in a thatch hut.

Seriously, what marginal percentage of temperature increase are we talking about, all things considered? If you have and average home with 3 ceiling fans, and they're all thee running, will they even increase the temperature by 1F?


28.
Mon, 07/22/2013 - 10:22

To Ice Rabbit
by Carl Seville, GBA Advisor

Helpful? 0

Oh please yourself. My issues about fans heating up a room is only in the context of them running when no one can feel the air on their skin. In that case, not only is all the energy used to operate the fan 100% wasted, there is some heat, however marginal an amount, that is added to the room. I would never suggest that you should not use a fan because it adds heat to the room, only that you shouldn't use a fan if you aren't sitting in its air flow. It is sort of a zero sum game - if you make good use of a fan by raising the temperature on your AC and turning them off when you leave the room - excellent. If you leave them on when not around and/or don't adjust your AC temperature up, then it is a 100% waste of energy and lost opportunity to save. There really isn't much middle ground in this discussion.


29.
Mon, 07/22/2013 - 19:16

I avoid wearing leaves
by Curt Kinder

Helpful? -1

Around. Rabbits. They. Might. Get. Chewed. Off.


30.
Tue, 07/23/2013 - 06:46

Edited Tue, 07/23/2013 - 06:50.

Do fans not make air move?
by Steve P

Helpful? 0

I have a post & beam cottage in Maine and when we are not there, it is closed up with an HRV running on a timer for about half the day. Heat is kept low in the winter (40F inside) as an alternative to winterizing. I also keep a ceiling fan running on low speed to encourage air circulation, since a "cold spot" in the winter could result in frozen pipes. In the summer, I just assumed it would keep heat buildup down as it's in an area with a cathedral ceiling.

Now, obviously, in the winter any heat from the motor is not wasted as it is captured within the building envelope. In the summer? I don't know. It's been running pretty much non-stop for about five years now. I had to do some work near the fan last summer. Yes, the motor was warm - I would say 80F, just slightly above ambient. Running the fan, HRV and a fridge-freezer 365/24/7, my power bill is $23/mo, and Maine is known for expensive electricity. I suspect turning the fan off would slash the bill to $22 :-)

Some of the posts here appear to be ads for brands of fans. I am wary of any claim for an "efficient" fan (as contrasted with fan motors). Yes, big fans move more air and use more electricity, but I've looked at some of these over-advertised brands and it appears to be mostly hype.


31.
Tue, 07/23/2013 - 07:03

I'd turn that fan off in
by Curt Kinder

Helpful? 0

I'd turn that fan off in summer when home is unoccupied.

As to fan brands, Energy Star data, particularly CFM / Watt, is useful when choosing.


32.
Tue, 07/23/2013 - 11:31

And one more benefit of fans
by Steve P

Helpful? 1

As reported by the New York Times - they help keep mosquitoes at bay, by creating man-made "wind" which makes it more difficult for them to fly and disperses the odors they home in on

http://www.nytimes.com/2013/07/16/science/a-low-tech-mosquito-deterrent....


33.
Tue, 07/23/2013 - 22:23

That's funny and reminds me of a recent energy audit
by Curt Kinder

Helpful? -1

I gently admonished a client about leaving porch ceiling fans on 24/7, and he responded that doing so was necessary in order to stave off wasp nests being built.

That's a novel excuse!


34.
Wed, 07/24/2013 - 10:25

Legitimate Use of Cieling Fans
by James Echevarria

Helpful? 0

I believe I have a legitimate use for ceiling fans to run. Both in summer and winter. That is because in the winter I use a centrally located wood stove for 100% of our heat. That is minus the 2% from the fan. Then in the summer we use a single 10000 BTU window air conditioner to condition the house. Circulating the air for these two scenarios seems to be critical for more even temp distribution. Especially for the summer. Since the air conditioner is not centrally located. Please correct me if I am wrong.


35.
Wed, 07/24/2013 - 10:25

Now it's even gone partisan-political!?!
by Dana Dorsett

Helpful? 0

Apparently ceiling fans are in second place amongst "miscellaneous" annual power use in residential housing ( who knew?), right behind TVs, but right in there but slightly ahead of PCs & set-top boxes:

http://dqbasmyouzti2.cloudfront.net/content/images/articles/energy-hogs-...

But of course setting minimum efficiency standards on anything elicits a knee-jerk response from some quarters when there's a perception that partisan advantage can be gained from it:

http://www.greentechmedia.com/articles/read/Move-Over-Light-Bulb-Republi...


36.
Wed, 07/24/2013 - 11:17

fan efficiency
by Jon R

Helpful? 0

Fan efficiency varies by more than 500% between different makes and models; it's worth investigating. Turn then off when nobody is there and they are a bargain.

I have seen cases where no AC combined with high humidity and the cooling effect of a concrete floor caused mold. Leaving the fan on there made sense.


37.
Wed, 07/24/2013 - 11:28

Response to James Echevarria
by Carl Seville, GBA Advisor

Helpful? 0

James - without knowing the layout of your house it is hard to determine whether the fan usage in your case is appropriate, although I think that it may not be doing as much as you think. You might be better off with either box fans that move air horizontally or if you are ambitious installing some transfer ducts with in line fans between rooms.


38.
Thu, 07/25/2013 - 10:38

Turning me into a curmudgeon
by kim shanahan

Helpful? 0

Dear Carl,

Please, I need relationship advice. I shared this article with my girlfriend who has long insisted on keeping fans running in our Santa Fe home while we are both at work. Naturally she thinks this advice is a male conspiracy of geeky nerds who think they are so damn smart and who don't understand common sense.

Ok, so I think I've got her convinced that air flowing over our skin is what is keeping us cool and therefore the bedrooms, which are kept closed to keep the dogs out, do not need the fans running 24-7. Now she insists the living room fan should stay on to keep the dogs cool while we are at work. When I point out that dogs have no exposed skin and don't sweat, and therefore don't benefit from moving air, she gives me the withering look . Now she isn't speaking to me. Thanks Carl. Any more great advice?

Signed, In the doghouse with no fan.


39.
Thu, 07/25/2013 - 13:40

Not qualified Kim
by Carl Seville, GBA Advisor

Helpful? 0

Sorry pal but I can't help you with this one. I'm not qualified to offer couples counseling.


40.
Thu, 07/25/2013 - 22:31

I'm gonna side with the GF on
by Curt Kinder

Helpful? 0

I'm gonna side with the GF on this one - any surface, be it wet skin or dry dog fur, warmer than surrounding air, will transfer more heat to that surrounding air if that surrounding air is moving. The technical terms for the two scenarios are "forced" vs "natural" convection.

I can assure you that dogs and cats in hot houses with floor returns will sleep on or near said floor returns in search of cooling breezes. Their presence greatly decreases filter change intervals.

If you want to keep the girl, fan the dogs all day. Alternatively, simplify your life by losing both the dogs and the girl. That's my advice, but your call, since I haven't seen the girl.


41.
Fri, 07/26/2013 - 23:24

Male Conspiracy
by John Nicholas

Helpful? 0

Kim, You might look over the professors at your local college! One of them might at least get rid of the idea of a 'Male Conspiracy'. Who knows what else?


42.
Sun, 07/28/2013 - 13:13

Recruiting for the ceiling fan police
by Carl Seville, GBA Advisor

Helpful? 0

Just returned from a weekend at the beach and saw so many fans running on unoccupied porches that I am ready to print up citations and start tacking them to doors of homes when I see this behavior. Still working on appropriate punishment.


43.
Sun, 07/28/2013 - 22:10

I see the same thing from the vantage point of navigable waters
by Curt Kinder

Helpful? 0

Our highest value homes are along lakes creeks and rivers which I patrol every weekend. Yes, I see hundreds of fans turning over empty rooms.


Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!