6 ms·

The Revenge of the Circulating Fan

99 points by lispython 12y ago

mturmon 12y ago
The five ceiling fans in my Southern California house are on virtually nonstop, night and day, from July through September. I haven't done analysis, but anecdotally they make rooms feel a lot cooler. If you get quality fans, they are inaudible (at low speed) and seem to be trouble-free (i.e., no problems after ~10 years of this level of activity).
- jacquesm 12y ago
  Brushless AC motors (short circuit cage type) are extremely reliable, there are only two things that can happen: eventually the bearings will run out or the coils will short due to the mechanical friction resulting from the changing flux which tries to push the wire around. The stators are usually cast into a resin to counteract this as much as possible but in spite of that some freedom of movement usually remains.
kijin 12y ago
Apart from a few isolated statements that suggest using fans together with ACs (which, of course, is a totally reasonable thing to do), the overall tone of the article is very much "AC = evil, fan = cool." Unfortunately, fan-only cooling only works in a narrow range of climates. > For instance, instead of cooling down a space to 24°C (75°F), the aircon can cool it to 29°C (84°F), which is a comfortable temperature if combined with fans. Whether or not 29°C can be considered a "comfortable temperature", even with fans, depends a lot on other factors, the most important of which is humidity. 29°C at 30% humidity is very different from 29°C at 90% humidity. The former is common in Europe and the American West. The latter is much more common in the Southeast, as well as the majority of newly industrialized countries such as China and India. Try installing a radiant cooling system in one of those hot & humid places. See all that condensation on the walls? That's a recipe for explosive mold growth. All the fans in the world will not make that pesky H2O go away, since the air is already oversaturated with it. People can tolerate a lot of heat with nothing but a paper fan, but there's no alternative to a good ol' electron-guzzling compressor when it comes to humidity control. You might feel totally comfortable with a fan in your cool and dry Northern California summers, but be very careful before you try to generalize your energy-saving hack to different climates. There's a reason why millions of people won't give up their AC's for fans, and it's not because they don't know how to stay cool.
- macNchz 12y ago
  Exactly. There could be an alternative discussion about the sustainability of cities that are entirely AC dependent, but the suggestion that AC is simply a luxury that could be largely replaced by fans gives me the impression that the author hasn't spent much time in Houston, Atlanta or Washington DC in the summertime. I don't like AC all that much, but I don't think I could continue to live and work in NYC in the summer without it, nevermind somewhere further south, it's just too damn humid. Also, the author suggests leaving the air conditioning at a too-warm setting and supplementing it with fans...having experienced this as friends and family try to save money on cooling, I can't recommend it. At least with a typical residential HVAC system, it seems to me to make the air feel very stale, to where I'd much rather open a window even if it's sweltering outside.
  - kijin 12y ago
    HVAC systems should only circulate dry air. When they circulate lukewarm (read: insufficiently dehumidified) air, various smelly and unhealthy substances tend to accumulate in the ducts and filters. Stale air is a telltale sign that you've got a mycotoxin factory in your house.
  - cafard 12y ago
    I have made it through a number of Washington summers simply on fans. Now, I was in a deeply shaded neighborhood, and to be sure I did not sleep that well on the hot nights. I wouldn't do it now: for one thing, my wife would regard it as insane. The problem that occurs to from NYC is the noise that would come in through open windows.
- antimagic 12y ago
  False dichotomy. Fans can be used in conjunction with AC, greatly reducing the energy required by the AC, by making higher temperatures acceptable.
  - kijin 12y ago
    Of course it's a false dichotomy. Did you read the first sentence of my comment?
eclipxe 12y ago
The first fan pic in the article - the Big Ass Fan Haiku - awesome fan with lots of tech
jrapdx3 12y ago
No question ceiling (and other) fans are useful for cooling, also for heating by distributing warm air that otherwise pools overhead, especially in high-ceiling rooms. A cool water radiant system certainly seems it would save electric power. But I wonder if such use of water is potentially a problem in regions where water is a precious commodity. Growing up in the desert of Arizona in the era before air conditioning became widespread, there were interesting approaches to dealing with summer heat. Relevant here, the "swamp cooler" was a fixture in most homes. Sort of a combination of moving air and water methods, the cooler worked by running a squirrel cage fan in a slatted metal box and water dripped through material mounted on the interior box surface. Air flowed through the openings in the box, evaporating water and cooling the stream of air which was piped into the house though metal ducting. This worked great when the air is dry. The later summer monsoon season was its ruin: high humidity did not favor evaporation, or much cooling at all. It was enough to make people think air conditioning would be a really good thing.
cornewut 12y ago
The article mentions that fans don't work when air temperature is higher than that of the skin(35C). This actually is not correct as increased air flow facilitates evaporation (making sweating more effective).
- kijin 12y ago
  Only if humidity is low enough. Otherwise, moisture from the air will condense on your skin (making sweating completely ineffective).
  - rurounijones 12y ago
    Helloooo Japanese summers.
qwerta 12y ago
Other option is to go underground. On continental climate it also saves winter heating costs
- girzel 12y ago
  Why isn't this considered as a solution more often? Is it just because construction costs go up, or for reasons of culture and habit? It seems like this is absolutely the best approach for stabilizing temperatures in both hot and cold climates. Might not work well in a place with a lot of ground water, I guess, but in general it seems like a win. Reduces building profiles, as well.
  - rprospero 12y ago
    While I've read enough Asimov to believe that the future is underground, I'll also be the first to admit that the lack of windows is a major problem with the system. You both lose natural light and the cooling air currents provided by the wind.
    - girzel 12y ago
      Well I didn't mean all the way underground -- I think you'd get substantial benefits from going three-quarters down on the ground floor. If there's only one floor, skylights do the trick. For multiple stories, high windows, and then fans circulating air between floors. Hmm, I guess this is getting a little expensive after all...
  - seanmcdirmid 12y ago
    We like our views. Also, fire code wouldn't really allow for it in most developed countries...sinking windows is quite expensive.
- pcrh 12y ago
  A traditional Persian method of cooling was to build windcatchers combined with an underground intake that was routed underground where it cooled. https://en.wikipedia.org/wiki/File:Qanat_wind_tower.svg https://en.wikipedia.org/wiki/File:Qanat_wind_tower.svg
carlob 12y ago
I think another solution that is often overlooked in the US is the passive flow caused by open windows. I've been to so many buildings in the US where it's impossible to have windows wide open and in some cases open at all. I tend to think this is a bit like suburbia: a design choice made when energy was much cheaper.
- ZeroGravitas 12y ago
  The article also suggests this is due to comfort regulations about airflow, which were originated by the heating and cooling industry and so are not likely to be friendly to methods that don't involve their products.
- pimlottc 12y ago
  I've heard some fascinating stuff about passive airflow architecture. The floor plans of old buildings were often laid out in very specific and sophisticated arrangements designed to take advantage of local prevailing winds and weather patterns so that opening certain pairs of windows at certain times of day would effectively ventilate the entire structure. It's interesting to also think of the secondary effects we've lost by effectively sealing out the outside world and living in a closed box.
  - girzel 12y ago
    I would love to read a book on this: How far can you get relying purely on design and structure, not technology. "Passive" solutions, as you say. A fascinating topic.
    - rizumu 12y ago
      Earthships, if you are unfamiliar with them, are a great place to start: http://earthship.com/ http://earthship.com/
    - jacquesm 12y ago
      100% passive is possible today. http://en.wikipedia.org/wiki/Solar_Umbrella_house http://en.wikipedia.org/wiki/Solar_Umbrella_house
callesgg 12y ago
"AC accounts for approximately 20% of year-round electricity consumption by American households, and 15% of total electricity use. [1] The widespread use of AC explains in large part why Americans use so much more electricity than Europeans: AC electricity use by an American household equals 60% of all electricity used by the average European household. [2]" That math with that statment does not realy work.
- vinw 12y ago
  I think it can hold together if there is a lot of non-domestic AC use in the US.
- nyc640 12y ago
  I think it means.. American Household : [XXXXXX------------------------] European Household : [----------] Where the X's are electricity usage by American households on air conditioning (20% of total electricity use), which is equal to 60% of all electricity used by a European household.
  - TeMPOraL 12y ago
    Comparing this to jacquesm's excellent and detailed explanation I have to admit that sometimes a simple picture can really be worth a thousand words.
    - jacquesm 12y ago
      He has my vote.
  - callesgg 12y ago
    Yep ;)
  - DamnYuppie 12y ago
    Europe is also much cooler then most of the USA in the summer. You all are welcome to come and hangout in the south any summer you want, then you will have a better understanding of the AC usage here. If I lived in Europe I probably wouldn't need AC either.
mrfusion 12y ago
Has anyone installed a whole house fan? I've heard they can rapidly cool your house to the outside temp at night? I can't decide if it would hurt resale value too much to have a giant fan vent in the middle of the ceiling though.
- kd0amg 12y ago
  My apartment has one, but it's too loud to run it overnight. The vent itself doesn't seem like a big deal though. It falls shut when the fan isn't in use.
  - mrfusion 12y ago
    Can it cool down your place really fast? For example in my house, when it's 80 degrees inside and 65 outside, I can open all the windows, and it gets down to 75 overnight :-(
    - canvia 12y ago
      They move a lot of air and do cool things down quickly. Just make sure there aren't any fresh skunks outside before you turn it on.
    - kd0amg 12y ago
      I don't know. We don't run it overnight. I just use a pair of box fans (≈ intake + exhaust) to push cool night air through my room.
- brixon 12y ago
  It has louvers so when the fan is off it is not visible. We had on when I was a kid. It is much cheaper than box fans in every window and more aesthetic.
- agarden 12y ago
  I lived in a house where one was installed. It could cool down the whole house in half an hour. Operation was noisy.
- 12y ago
a2tech 12y ago
As someone that lives in a house built in 1860 (so windows open to allow passive airflow) that has been retrofitted with ceiling fans and AC I can tell you that if you're in a region with any sort of humidity that AC is unbeatable. The ceiling fan is great if its slightly warm, not humid, and you have the windows open.
ferongr 12y ago
I don't know, I can't say I agree with the article. I grew up (and still live) in a small apartment in Greece. My family had fans (because air-conditioning was expensive back in the day) all around the house. We "managed", but it was definitely not comfortable when ambient temperature increased above 32C. After installing air-conditioning (3 12000 BTU ductless mini-splits) everything changed. Summers were finally comfortable afterwards and today I would never think of decommissioning the A/C units, regardless of electricity costs.
- papercrane 12y ago
  Article says the limit of this is 30C. I don't think the argument here is that fans can replace all uses of AC, but rather can supplement them.
- CanSpice 12y ago
  The article makes the point that A/C in conjunction with fans can reduce the amount of energy needed to reach the same comfort levels. You don't need to remove the A/C if you install fans, but you can set the A/C thermostat to a higher temperature (which saves on electricity use and cost) and turn on a fan to get the same comfort level.
jrkatz 12y ago
I live on the first floor of a house in Boston, and this summer made it through without AC. By keeping heavy curtains drawn and closing both layers of the double windows during the day, then opening windows at night and using fans to draw cooler air through the apartment, I was able to keep the apartment relatively cool throughout the summer. Sure, there were nights my apartment still hit 87F indoors by the time I was going to bed -- a week of nights that don't dip below 80 will do that -- but it doesn't take that long to get used to it and the breeze from open windows and running fans made it much more tolerable. There are a lot of places in the US that benefit tremendously from AC -- I grew up in the Mojave desert and there is little arguing with AC at 110F -- nonetheless the the machines are overused. If more people decided to tolerate 80F as room temperature, even without active measures to replace AC in their homes, we'd see a precipitous decline in energy usage. Add to that careful control of airflow and insulation and many regions simply don't need AC. Meanwhile, I am at my office, and the AC is run so high in the summer that many people wear jackets indoors year round here. Lovely.
- benologist 12y ago
  I grew up in Australia, our summers were also in the 80 - 110 range and if we wanted AC that meant going to the mall.
- 300bps 12y ago
  the machines are overused. If more people decided to tolerate 80F as room temperature...we'd see a precipitous decline in energy usage When I first moved into my current house I was setting the air conditioning at 78 degrees. Then I had my central AC unit serviced and the tech showed me little dots of mold throughout the inside of the unit in the basement. He told me not to set the thermostat above 75 degrees in the summer time because it doesn't get enough humidity out of the air. He also said to make sure I kept a dehumidifier running in the basement. Now I keep the thermostat on 75 and keep the basement at 50% relative humidity using a dehumidifier in the summer. I also ended up installing a UV light inside the basement unit myself to kill microorganisms. So it's easy to say to just tolerate higher temperature but the unfortunate thing is that high humidity levels inside a home can lead to serious issues.
kingmanaz 12y ago
The Bonelli house in Kingman, Arizona was built before central air conditioning became common in homes. Temperatures in Kingman regularly reach > 110F (43C) in the summer, yet the Bonelli house was comfortable without air conditioning or fans. To cool the house, a trap door in the center of the first floor was opened, drafting cool air from the deep, unfinished basement, through the intervening floors, and out a roof cupola. The system was passive and still functions today. http://kingmanhistoricdistrict.com/homes/bonelli-house/index.htm http://kingmanhistoricdistrict.com/homes/bonelli-house/index... Other locals would hang burlap or bedsheets over open windows, periodically dampening the material with a hose. The hot breezes would blow through the wet material, evaporating the moisture, and cooling the air. Many older homes still have the blanket hooks above windows, though residents have long since switched to air conditioners or swamp coolers for cooling.
ScottBurson 12y ago
If anyone is looking for a product recommendation, permit me to suggest the Fanimation Landan [0]. My wife and I have one in the living room and love it. 6 speeds, remote control, LED lights built in (dimmable using the remote), efficient DC motor. [0] http://www.fanimation.com/products/landan/ http://www.fanimation.com/products/landan/
pnathan 12y ago
I've lived with box fans for years. This is our second summer in the Pacific Northwest, and our current apartment has no air movement. I.e., you can have box fans in the windows all night, and the kitchen is this mass of warm air when you get up. The apartment heats up very quickly and loses heat slowly for some reason. The apartment quickly reaches 78-80 degrees and is really unpleasant. So this summer indicated an AC purchase for the bedroom was a good idea. It's been extremely nice to sleep in a cool & dry room. I'd be quite happy to have a residence that had decent air movement design, along with ceiling fans, but I don't think I'm giving up the bedroom AC.
kazinator 12y ago
> [Fans] can only provide cooling at air temperatures below the mean skin temperature, which is about 35°C (95°F). Fans cannot cool people above that treshold, because moving air cannot reduce the skin temperature below the ambient temperature – no matter how high the air speed. The statement applies to passive heat sinks. If a device's heat sink has a surface temperature of 35°C, then blowing 40°C air across it faster will not only help, but it will be counterproductive: the warmer air heats the heat-sink, and moving air does it faster. In 40°C relatively dry air, your skin is 35°C only because of active heat removal: evaporation. This changes the picture. Moving air can speed this up even though it is warmer. If the air doesn't move, then evaporation wraps you in a blanket of humid air. Ventilation displaces the humid air, replacing it with dry air that can take up moisture.

99 points by lispython 12y ago

The five ceiling fans in my Southern California house are on virtually nonstop, night and day, from July through September. I haven't done analysis, but anecdotally they make rooms feel a lot cooler. If you get quality fans, they are inaudible (at low speed) and seem to be trouble-free (i.e., no problems after ~10 years of this level of activity).

jacquesm 12y ago
Brushless AC motors (short circuit cage type) are extremely reliable, there are only two things that can happen: eventually the bearings will run out or the coils will short due to the mechanical friction resulting from the changing flux which tries to push the wire around. The stators are usually cast into a resin to counteract this as much as possible but in spite of that some freedom of movement usually remains.

kijin 12y ago

Apart from a few isolated statements that suggest using fans together with ACs (which, of course, is a totally reasonable thing to do), the overall tone of the article is very much "AC = evil, fan = cool." Unfortunately, fan-only cooling only works in a narrow range of climates. > For instance, instead of cooling down a space to 24°C (75°F), the aircon can cool it to 29°C (84°F), which is a comfortable temperature if combined with fans. Whether or not 29°C can be considered a "comfortable temperature", even with fans, depends a lot on other factors, the most important of which is humidity. 29°C at 30% humidity is very different from 29°C at 90% humidity. The former is common in Europe and the American West. The latter is much more common in the Southeast, as well as the majority of newly industrialized countries such as China and India. Try installing a radiant cooling system in one of those hot & humid places. See all that condensation on the walls? That's a recipe for explosive mold growth. All the fans in the world will not make that pesky H2O go away, since the air is already oversaturated with it. People can tolerate a lot of heat with nothing but a paper fan, but there's no alternative to a good ol' electron-guzzling compressor when it comes to humidity control. You might feel totally comfortable with a fan in your cool and dry Northern California summers, but be very careful before you try to generalize your energy-saving hack to different climates. There's a reason why millions of people won't give up their AC's for fans, and it's not because they don't know how to stay cool.

macNchz 12y ago
Exactly. There could be an alternative discussion about the sustainability of cities that are entirely AC dependent, but the suggestion that AC is simply a luxury that could be largely replaced by fans gives me the impression that the author hasn't spent much time in Houston, Atlanta or Washington DC in the summertime. I don't like AC all that much, but I don't think I could continue to live and work in NYC in the summer without it, nevermind somewhere further south, it's just too damn humid. Also, the author suggests leaving the air conditioning at a too-warm setting and supplementing it with fans...having experienced this as friends and family try to save money on cooling, I can't recommend it. At least with a typical residential HVAC system, it seems to me to make the air feel very stale, to where I'd much rather open a window even if it's sweltering outside.
- kijin 12y ago
  HVAC systems should only circulate dry air. When they circulate lukewarm (read: insufficiently dehumidified) air, various smelly and unhealthy substances tend to accumulate in the ducts and filters. Stale air is a telltale sign that you've got a mycotoxin factory in your house.
- cafard 12y ago
  I have made it through a number of Washington summers simply on fans. Now, I was in a deeply shaded neighborhood, and to be sure I did not sleep that well on the hot nights. I wouldn't do it now: for one thing, my wife would regard it as insane. The problem that occurs to from NYC is the noise that would come in through open windows.
antimagic 12y ago
False dichotomy. Fans can be used in conjunction with AC, greatly reducing the energy required by the AC, by making higher temperatures acceptable.
- kijin 12y ago
  Of course it's a false dichotomy. Did you read the first sentence of my comment?

eclipxe 12y ago

The first fan pic in the article - the Big Ass Fan Haiku - awesome fan with lots of tech

jrapdx3 12y ago

No question ceiling (and other) fans are useful for cooling, also for heating by distributing warm air that otherwise pools overhead, especially in high-ceiling rooms. A cool water radiant system certainly seems it would save electric power. But I wonder if such use of water is potentially a problem in regions where water is a precious commodity. Growing up in the desert of Arizona in the era before air conditioning became widespread, there were interesting approaches to dealing with summer heat. Relevant here, the "swamp cooler" was a fixture in most homes. Sort of a combination of moving air and water methods, the cooler worked by running a squirrel cage fan in a slatted metal box and water dripped through material mounted on the interior box surface. Air flowed through the openings in the box, evaporating water and cooling the stream of air which was piped into the house though metal ducting. This worked great when the air is dry. The later summer monsoon season was its ruin: high humidity did not favor evaporation, or much cooling at all. It was enough to make people think air conditioning would be a really good thing.

cornewut 12y ago

The article mentions that fans don't work when air temperature is higher than that of the skin(35C). This actually is not correct as increased air flow facilitates evaporation (making sweating more effective).

kijin 12y ago
Only if humidity is low enough. Otherwise, moisture from the air will condense on your skin (making sweating completely ineffective).
- rurounijones 12y ago
  Helloooo Japanese summers.

qwerta 12y ago

Other option is to go underground. On continental climate it also saves winter heating costs

girzel 12y ago
Why isn't this considered as a solution more often? Is it just because construction costs go up, or for reasons of culture and habit? It seems like this is absolutely the best approach for stabilizing temperatures in both hot and cold climates. Might not work well in a place with a lot of ground water, I guess, but in general it seems like a win. Reduces building profiles, as well.
- rprospero 12y ago
  While I've read enough Asimov to believe that the future is underground, I'll also be the first to admit that the lack of windows is a major problem with the system. You both lose natural light and the cooling air currents provided by the wind.
  - girzel 12y ago
    Well I didn't mean all the way underground -- I think you'd get substantial benefits from going three-quarters down on the ground floor. If there's only one floor, skylights do the trick. For multiple stories, high windows, and then fans circulating air between floors. Hmm, I guess this is getting a little expensive after all...
- seanmcdirmid 12y ago
  We like our views. Also, fire code wouldn't really allow for it in most developed countries...sinking windows is quite expensive.
pcrh 12y ago
A traditional Persian method of cooling was to build windcatchers combined with an underground intake that was routed underground where it cooled. https://en.wikipedia.org/wiki/File:Qanat_wind_tower.svg https://en.wikipedia.org/wiki/File:Qanat_wind_tower.svg

carlob 12y ago

I think another solution that is often overlooked in the US is the passive flow caused by open windows. I've been to so many buildings in the US where it's impossible to have windows wide open and in some cases open at all. I tend to think this is a bit like suburbia: a design choice made when energy was much cheaper.

ZeroGravitas 12y ago
The article also suggests this is due to comfort regulations about airflow, which were originated by the heating and cooling industry and so are not likely to be friendly to methods that don't involve their products.
pimlottc 12y ago
I've heard some fascinating stuff about passive airflow architecture. The floor plans of old buildings were often laid out in very specific and sophisticated arrangements designed to take advantage of local prevailing winds and weather patterns so that opening certain pairs of windows at certain times of day would effectively ventilate the entire structure. It's interesting to also think of the secondary effects we've lost by effectively sealing out the outside world and living in a closed box.
- girzel 12y ago
  I would love to read a book on this: How far can you get relying purely on design and structure, not technology. "Passive" solutions, as you say. A fascinating topic.
  - rizumu 12y ago
    Earthships, if you are unfamiliar with them, are a great place to start: http://earthship.com/ http://earthship.com/
  - jacquesm 12y ago
    100% passive is possible today. http://en.wikipedia.org/wiki/Solar_Umbrella_house http://en.wikipedia.org/wiki/Solar_Umbrella_house

callesgg 12y ago

"AC accounts for approximately 20% of year-round electricity consumption by American households, and 15% of total electricity use. [1] The widespread use of AC explains in large part why Americans use so much more electricity than Europeans: AC electricity use by an American household equals 60% of all electricity used by the average European household. [2]" That math with that statment does not realy work.

vinw 12y ago
I think it can hold together if there is a lot of non-domestic AC use in the US.
nyc640 12y ago
I think it means.. American Household : [XXXXXX------------------------] European Household : [----------] Where the X's are electricity usage by American households on air conditioning (20% of total electricity use), which is equal to 60% of all electricity used by a European household.
- TeMPOraL 12y ago
  Comparing this to jacquesm's excellent and detailed explanation I have to admit that sometimes a simple picture can really be worth a thousand words.
  - jacquesm 12y ago
    He has my vote.
- callesgg 12y ago
  Yep ;)
- DamnYuppie 12y ago
  Europe is also much cooler then most of the USA in the summer. You all are welcome to come and hangout in the south any summer you want, then you will have a better understanding of the AC usage here. If I lived in Europe I probably wouldn't need AC either.

mrfusion 12y ago

Has anyone installed a whole house fan? I've heard they can rapidly cool your house to the outside temp at night? I can't decide if it would hurt resale value too much to have a giant fan vent in the middle of the ceiling though.

kd0amg 12y ago
My apartment has one, but it's too loud to run it overnight. The vent itself doesn't seem like a big deal though. It falls shut when the fan isn't in use.
- mrfusion 12y ago
  Can it cool down your place really fast? For example in my house, when it's 80 degrees inside and 65 outside, I can open all the windows, and it gets down to 75 overnight :-(
  - canvia 12y ago
    They move a lot of air and do cool things down quickly. Just make sure there aren't any fresh skunks outside before you turn it on.
  - kd0amg 12y ago
    I don't know. We don't run it overnight. I just use a pair of box fans (≈ intake + exhaust) to push cool night air through my room.
brixon 12y ago
It has louvers so when the fan is off it is not visible. We had on when I was a kid. It is much cheaper than box fans in every window and more aesthetic.
agarden 12y ago
I lived in a house where one was installed. It could cool down the whole house in half an hour. Operation was noisy.
12y ago

a2tech 12y ago

As someone that lives in a house built in 1860 (so windows open to allow passive airflow) that has been retrofitted with ceiling fans and AC I can tell you that if you're in a region with any sort of humidity that AC is unbeatable. The ceiling fan is great if its slightly warm, not humid, and you have the windows open.

ferongr 12y ago

I don't know, I can't say I agree with the article. I grew up (and still live) in a small apartment in Greece. My family had fans (because air-conditioning was expensive back in the day) all around the house. We "managed", but it was definitely not comfortable when ambient temperature increased above 32C. After installing air-conditioning (3 12000 BTU ductless mini-splits) everything changed. Summers were finally comfortable afterwards and today I would never think of decommissioning the A/C units, regardless of electricity costs.

papercrane 12y ago
Article says the limit of this is 30C. I don't think the argument here is that fans can replace all uses of AC, but rather can supplement them.
CanSpice 12y ago
The article makes the point that A/C in conjunction with fans can reduce the amount of energy needed to reach the same comfort levels. You don't need to remove the A/C if you install fans, but you can set the A/C thermostat to a higher temperature (which saves on electricity use and cost) and turn on a fan to get the same comfort level.

jrkatz 12y ago

I live on the first floor of a house in Boston, and this summer made it through without AC. By keeping heavy curtains drawn and closing both layers of the double windows during the day, then opening windows at night and using fans to draw cooler air through the apartment, I was able to keep the apartment relatively cool throughout the summer. Sure, there were nights my apartment still hit 87F indoors by the time I was going to bed -- a week of nights that don't dip below 80 will do that -- but it doesn't take that long to get used to it and the breeze from open windows and running fans made it much more tolerable. There are a lot of places in the US that benefit tremendously from AC -- I grew up in the Mojave desert and there is little arguing with AC at 110F -- nonetheless the the machines are overused. If more people decided to tolerate 80F as room temperature, even without active measures to replace AC in their homes, we'd see a precipitous decline in energy usage. Add to that careful control of airflow and insulation and many regions simply don't need AC. Meanwhile, I am at my office, and the AC is run so high in the summer that many people wear jackets indoors year round here. Lovely.

benologist 12y ago
I grew up in Australia, our summers were also in the 80 - 110 range and if we wanted AC that meant going to the mall.
300bps 12y ago
the machines are overused. If more people decided to tolerate 80F as room temperature...we'd see a precipitous decline in energy usage When I first moved into my current house I was setting the air conditioning at 78 degrees. Then I had my central AC unit serviced and the tech showed me little dots of mold throughout the inside of the unit in the basement. He told me not to set the thermostat above 75 degrees in the summer time because it doesn't get enough humidity out of the air. He also said to make sure I kept a dehumidifier running in the basement. Now I keep the thermostat on 75 and keep the basement at 50% relative humidity using a dehumidifier in the summer. I also ended up installing a UV light inside the basement unit myself to kill microorganisms. So it's easy to say to just tolerate higher temperature but the unfortunate thing is that high humidity levels inside a home can lead to serious issues.

kingmanaz 12y ago

The Bonelli house in Kingman, Arizona was built before central air conditioning became common in homes. Temperatures in Kingman regularly reach > 110F (43C) in the summer, yet the Bonelli house was comfortable without air conditioning or fans. To cool the house, a trap door in the center of the first floor was opened, drafting cool air from the deep, unfinished basement, through the intervening floors, and out a roof cupola. The system was passive and still functions today. http://kingmanhistoricdistrict.com/homes/bonelli-house/index.htm http://kingmanhistoricdistrict.com/homes/bonelli-house/index... Other locals would hang burlap or bedsheets over open windows, periodically dampening the material with a hose. The hot breezes would blow through the wet material, evaporating the moisture, and cooling the air. Many older homes still have the blanket hooks above windows, though residents have long since switched to air conditioners or swamp coolers for cooling.

ScottBurson 12y ago

If anyone is looking for a product recommendation, permit me to suggest the Fanimation Landan [0]. My wife and I have one in the living room and love it. 6 speeds, remote control, LED lights built in (dimmable using the remote), efficient DC motor. [0] http://www.fanimation.com/products/landan/ http://www.fanimation.com/products/landan/

pnathan 12y ago

I've lived with box fans for years. This is our second summer in the Pacific Northwest, and our current apartment has no air movement. I.e., you can have box fans in the windows all night, and the kitchen is this mass of warm air when you get up. The apartment heats up very quickly and loses heat slowly for some reason. The apartment quickly reaches 78-80 degrees and is really unpleasant. So this summer indicated an AC purchase for the bedroom was a good idea. It's been extremely nice to sleep in a cool & dry room. I'd be quite happy to have a residence that had decent air movement design, along with ceiling fans, but I don't think I'm giving up the bedroom AC.

kazinator 12y ago

> [Fans] can only provide cooling at air temperatures below the mean skin temperature, which is about 35°C (95°F). Fans cannot cool people above that treshold, because moving air cannot reduce the skin temperature below the ambient temperature – no matter how high the air speed. The statement applies to passive heat sinks. If a device's heat sink has a surface temperature of 35°C, then blowing 40°C air across it faster will not only help, but it will be counterproductive: the warmer air heats the heat-sink, and moving air does it faster. In 40°C relatively dry air, your skin is 35°C only because of active heat removal: evaporation. This changes the picture. Moving air can speed this up even though it is warmer. If the air doesn't move, then evaporation wraps you in a blanket of humid air. Ventilation displaces the humid air, replacing it with dry air that can take up moisture.