Does a ceiling fan lower a room's temperature?

[ohm]

In a closed room with no heating or cooling does the fan lower the room temperature?:smile:

[billsnuff]

Since we live in the lower portion of the room I would think that it would actually raises the temp , relative to our location, as the air circulation would tend to avg the temp between warm at the ceiling and cool at the floor, regardless of the of the direction of the fan. JMSO

[hillbilly]

In a closed room with no heating or cooling does the fan lower the room temperature?:smile:

My 2 cents...

All in all.....NO.

It will be cooler in the air stream (that the fan creates).
This is because the fans blades compress the air (small amount), and cause the air to release heat.
As the air moves away from the fan blades (expands), it will absorb heat, and make the air (stream) cooler.

Also, as the air blows across your skin, it will cause sweat to evaporate, absorbing heat, and causing your skin surface temperature to go down....cooling you off.

It's kind of like a car air conditioning system, only with the condensor in the passenger compartment....it's usually under the hood.
The air will be cool as it leaves the evaporator, and be hot when it leaves the condensor.

If you exclude any heat gain or loss thru the wall of the room and run the fan for a period of time, when you turn the fan off, and the room temperature stabilizes, it will be warmer than before you began.
This is because the fan will add heat to the room.
So, if the fan is in a closed room, it will ultimately make the room warmer.

steve

[electricmanscott]

In a closed room with no heating or cooling does the fan lower the room temperature?:smile:


No, it does not.

[rich000]

No. Put a thermometer in the room without the fan running and check the temperature. Turn on the fan and then check the temperature.

Tell us what you find out.

CFs cool by windchill. Inanimate objects do not feel windchill. You need water to experience wind chill.

Now, if you use a wet bulb thermometer, you might get a different temperature.

However, the home's air conditioner uses a thermostat that is probably not a wet bulb.

So, if you leave the room, turn off the fan.

[iwire]

If you do the thermometer deal you would really want one at the floor and one at the ceiling, before starting the fan the air at the ceiling will be warmer then the air at the floor.

Start the fan and the temps will equalize, so the entire room will be equal temperature. As the others have stated you will feel cooler due to the breeze.

All that said the fan actually adds a bit of heat to the room from the motor but that amount is fairly small.

[Dennis Alwon]

It feels good because of the wind chill factor.

[George Stolz]

I wonder if the heat generated by the fan motor would be offset by the heat lost by air molecules striking the walls of the room, imparting their thermal energy to the walls?

[480sparky]

It also depends on if the windows are open and it's cooler outside. The fan will move the air around, and lower the temperature quicker than if there was no air movement.

[ohm]

I must confess I asked this same question in a different Forum but it was several days before I got the same answers as this Forum has settled on.

The fan only raises the temperature in a closed room and waste energy.

If a person is present evaporative cooling occurs because of the moisture on their skin.

Thanks all.:grin: :grin:

[ElectricianJeff]

Not to highjack this thread but............

Does it really make a difference which way the fan spins? I know your suppose to switch them with the change of seasons but never can remember.

I always leave them in the factory direction when installing regardless of the season.

[ultramegabob]

Not to highjack this thread but............

Does it really make a difference which way the fan spins? I know your suppose to switch them with the change of seasons but never can remember.

I always leave them in the factory direction when installing regardless of the season.


up in the winter to circulate the heat around, down in the summer to feel the breeze.

[cal1947]

actually the fan should blow up in the summer and down in the winter,cool air falls ,warm air raises

[Dennis Alwon]

actually the fan should blow up in the summer and down in the winter,cool air falls ,warm air raises

I agree that's what the manufacturers recommend but my experience is just the opposite. In the summer I want to feel the air on me and the winter I don't want that wind chill effect.

[zog]

and the winter I don't want that wind chill effect.

Right, these NC winters are rough :)

[ohm]

I agree that's what the manufacturers recommend but my experience is just the opposite. In the summer I want to feel the air on me and the winter I don't want that wind chill effect.

I tend to agree w/ Dennis I wonder hy the manufacturers the opposite?:confused:

[Dennis Alwon]

Right, these NC winters are rough :)

I use the fan to move the air from my wood stove. It pushes the air down the hall to the col air return and then we run the fan on the furnace to circulate the air. Works pretty well.

It gets cold here at times but not for long as you well know.:smile:

[ohm]

I use the fan to move the air from my wood stove. It pushes the air down the hall to the col air return and then we run the fan on the furnace to circulate the air. Works pretty well.

It gets cold here at times but not for long as you well know.:smile:

Sounds like a good idea, I'll bet you really miss those big energy bills.

I just wired a big addition to my sister-in-laws cabin in Tenn. The're going to try & heat a two story 3000 sq ft great room with just a wood burner. I suggested they use lots of ceiling fans. And, pull warm air into the bedrooms with in-wall fans then exhaust it back into the great room with another fan. They could even install T-stats on the fans like some of the big atruim hotels.

What do you think?

[Dennis Alwon]

Sounds like a good idea, I'll bet you really miss those big energy bills.

I just wired a big addition to my sister-in-laws cabin in Tenn. The're going to try & heat a two story 3000 sq ft great room with just a wood burner. I suggested they use lots of ceiling fans. And, pull warm air into the bedrooms with in-wall fans then exhaust it back into the great room with another fan. They could even install T-stats on the fans like some of the big atruim hotels.

What do you think?

I think that is not a cabin..:grin: Are you serious- a great room that is 3000 sq. ft or did you mean 300 sq. ft. One is 50 feet by 60 feet, etc or a 15 by 20.

I don't believe I have ever seen one room that big in a house.

What do I think????
I think there are stoves that will heat a wide open room like that but they will be logging all day just for heat.

[ohm]

I think that is not a cabin..:grin: Are you serious- a great room that is 3000 sq. ft or did you mean 300 sq. ft. One is 50 feet by 60 feet, etc or a 15 by 20.

I don't believe I have ever seen one room that big in a house.

What do I think????
I think there are stoves that will heat a wide open room like that but they will be logging all day just for heat.

Yea, 50' x 60' w/ 17' ceiling etc. w/ 11 ceiling fans. Not your typ. great room. It really needs a stuffed grizzly bear in the corner.

Maybe an overkill (pun intended).

[LarryFine]

actually the fan should blow up in the summer and down in the winter,cool air falls ,warm air raises I agree that's what the manufacturers recommend . . .I've never seen that recommended. I always see down in summer and up in winter, and that's what I recommend to people.

"They're reversible? How?"

And no, fans don't cool a room, but they do destratify. That's the purpose of blowing up in winter. Otherwise, why have it on?

[iwire]

This is how I have always heard it, and how I run mine.

http://www.farreys.com/i/ceiling_fans_faq/air_flow_summer.gif
Summer

http://www.farreys.com/i/ceiling_fans_faq/air_flow_winter.gif
Winter

[Buck Parrish]

I just installed some fans in a bar. Their on one down rod but have two individual fans. You can point one up and one down.. Problem solved.

My house has the HVAC returns in the cieling above the fans.
That makes a difference.

[LarryFine]

This is how I have always heard it, and how I run mine.

http://www.farreys.com/i/ceiling_fans_faq/air_flow_summer.gif
Summer

http://www.farreys.com/i/ceiling_fans_faq/air_flow_winter.gif
WinterExactamundo!

[LarryFine]

I just installed some fans in a bar. Their on one down rod but have two individual fans. You can point one up and one down.Won't they end up with mini-climate zones and little tornados? :)

[iwire]

Exactamundo!


AAAAAY…! http://forums.mikeholt.com/images/icons/icon14.gif

[roger]

Exactamundo!

Very good Larry.http://forums.mikeholt.com/images/icons/icon14.gif

Roger

[roger]

Won't they end up with mini-climate zones and little tornados? :)

Absolutely, this is a well known fact in the fan discussion world.

Roger

[wallyworld]

This is how I have always heard it, and how I run mine.

http://www.farreys.com/i/ceiling_fans_faq/air_flow_summer.gif
Summer

http://www.farreys.com/i/ceiling_fans_faq/air_flow_winter.gif
Winter
Some fan manufacturers will say reversing the fan so that it blows into the ceiling will do nothing. The air hits the ceiling and a large portion of the air stops.

[iwire]

Some fan manufacturers will say reversing the fan so that it blows into the ceiling will do nothing. The air hits the ceiling and a large portion of the air stops.

I imagine different rooms behave differently but I know the ceiling hugging fan in my living room moves a lot of air in either direction. :)

[LarryFine]

Some fan manufacturers will say reversing the fan so that it blows into the ceiling will do nothing. The air hits the ceiling and a large portion of the air stops. I imagine different rooms behave differently but I know the ceiling hugging fan in my living room moves a lot of air in either direction. :)The farther a fan is from the ceiling, the greater the air movement*, true enough, but there's no way the air just stops.

Got a smoke generator, Wally? You could do some experimenting.

* With the usual all-other-things-being-equal disclaimer.

[iwire]

Basically the ceiling presents the same restriction in either direction. :smile:

The fan can't push air down if air is not making it into the blades.

[LarryFine]

Basically the ceiling presents the same restriction in either direction. :smile:

The fan can't push air down if air is not making it into the blades. Correctamundo! http://forums.mikeholt.com/images/icons/icon14.gif

[roger]

Correctamundo! http://forums.mikeholt.com/images/icons/icon14.gif

Agreeamundohttp://forums.mikeholt.com/images/icons/icon14.gif

Roger

[jeremysterling]

I got a call the other day to install two customer supplied wall-mount shop fans in an automotive repair shop. I asked the mechanics where they wanted the fans mounted and they told me to mount them where they would blow hot air in the winter and cool air in the summer. They were serious. I told them, given the layout of their shop, I could guarantee the fans would blow hot air in the summer and cold air in the winter.

[220/221]

In a closed room with no heating or cooling does the fan lower the room temperature?



I didn't read the replies so I am sure it's been said.



No.

It evaporates the moisture on your skin making it feel cooler.




Technicaly it would raise the temp due to the motor heat.

[steelersman]

actually the fan should blow up in the summer and down in the winter,cool air falls ,warm air raises
you are wrong according to all the instructions with the fans I've bothered to check into

[steelersman]

I've never seen that recommended. I always see down in summer and up in winter, and that's what I recommend to people.

"They're reversible? How?"

And no, fans don't cool a room, but they do destratify. That's the purpose of blowing up in winter. Otherwise, why have it on?
you are correct. don't know how the others came to think the other way around

[steelersman]

This is how I have always heard it, and how I run mine.

http://www.farreys.com/i/ceiling_fans_faq/air_flow_summer.gif
Summer

http://www.farreys.com/i/ceiling_fans_faq/air_flow_winter.gif
Winter
you are correct. I don't know where the others come up with the other way around.

[zog]

This is the fan we have in our shop, we have the 24 foot version, BAF claims the wind chill effect lowers the temp 4-16 degrees, depending on speed. Lots of info on fans effect on temperature on this site.

http://www.bigassfans.com/

When we crank this baby up to 7 (It goes to 10) locker doors slam shut, papers fly all over, wheeled tables move around, but it sure cools the shop :)

[ceb58]

No. Put a thermometer in the room without the fan running and check the temperature. Turn on the fan and then check the temperature.

Tell us what you find out.

CFs cool by windchill. Inanimate objects do not feel windchill. You need water to experience wind chill.

Now, if you use a wet bulb thermometer, you might get a different temperature.

However, the home's air conditioner uses a thermostat that is probably not a wet bulb.

So, if you leave the room, turn off the fan.

The correct way to test the air is with a device called a sling psychrometer. It has two thermometers one is dry the other you wet a cotton ball that is wrapped around the bulb. The thermometer is attached to a string and handle you then twrill this contraption around for about a minute then read the two temps. If the ambient temp. is say 90 the wet one will be around 4-6 deg. cooler. As many have stated its the evaporating effect on your skin that makes it seem cooler. They use the same principle in chicken houses they have misters spraying a fine mist of water with large fans pulling air through the building feels good on a 100 deg. day:grin:

[LarryFine]

. . . BAF claims the wind chill effect lowers the temp 4-16 degrees, depending on speed.

When we crank this baby up to 7 . . . it sure cools the shop :)You do understand that this is perception only, right? It only feels cooler. Same as with the heat index, which takes huidity into account.

[LarryFine]

They use the same principle in chicken houses they have misters spraying a fine mist of water with large fans pulling air through the building feels good on a 100 deg. day:grin:A giant swamp cooler, aka an evaporative cooler.

[rich000]

The correct way to test the air is with a device called a sling psychrometer. It has two thermometers one is dry the other you wet a cotton ball that is wrapped around the bulb. The thermometer is attached to a string and handle you then twrill this contraption around for about a minute then read the two temps. If the ambient temp. is say 90 the wet one will be around 4-6 deg. cooler. As many have stated its the evaporating effect on your skin that makes it seem cooler. They use the same principle in chicken houses they have misters spraying a fine mist of water with large fans pulling air through the building feels good on a 100 deg. day:grin:

I've never seen a sling thermometer. I used to use a wet bulb thermometer in industrial spaces (could you sling yours around in a small space?). The wet bulb also had the cotton ball with an internal fan to pull the air across the wet cotton. I think I remember it being called a psychrometer. It definitely was not a sling though.

[hillbilly]

They use the same principle in chicken houses they have misters spraying a fine mist of water with large fans pulling air through the building feels good on a 100 deg. day:grin:

This process actually cools the air.
It requires about 970 btu's of heat to evaporate 1 pound of water.

As the water is sprayed into the air stream, it evaporates, and absorbs heat.
As long as the air doesn't reach saturation, the cooling effect will continue.
This requires "make-up" air, because if all the doors and windows are closed, the air would soon become saturated with water and the cooling (evaporation) would stop.

steve

[ohm]

This process actually cools the air.
It requires about 970 btu's of heat to evaporate 1 pound of water.

As the water is sprayed into the air stream, it evaporates, and absorbs heat.
As long as the air doesn't reach saturation, the cooling effect will continue.
This requires "make-up" air, because if all the doors and windows are closed, the air would soon become saturated with water and the cooling (evaporation) would stop.

steve

I didn't know the the BTU numbers hillbilly quoted but I see the football teams using "swamp coolers/misting fans" on the sidelines. I've also run a fan outside and injected a mist into the air with a garden hose. Man does it work!:grin: :grin:

[LarryFine]

Man does it work!:grin: :grin:Most technologies that mimic Mother Nature do.

[zog]

You do understand that this is perception only, right? It only feels cooler. Same as with the heat index, which takes huidity into account.

Huidity??

Yeah, I know it is perception only, but that hurricane force breeze feels good on a hot summer NC day.

[LarryFine]

Huidity??Yeah, huidity. Can't you read Engish? :D

Yeah, I know it is perception only, but that hurricane force breeze feels good on a hot summer NC day.Oh, tes.