Does a ceiling fan lower the ambient temperature of a room? - Page 2 - TigerDroppings.com

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Spankum
LSU Fan
Miss-sippi
Member since Jan 2007
31414 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

I'd love to conduct a poll to see how many think setting the thermostat lower makes the AC blow colder air.



this notion has pretty much made the locking thermostat standard equipment in office buildings...






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Zilla
LSU Fan
Friendswood, TX
Member since Jul 2005
9907 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

If the ac fan is in the on mode (as opposed to auto) it will certainly make the air coming out of the vents cooler than before the adjustment.


uh, wut ?






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Spock's Eyebrow
LSU Fan
Member since May 2012
2874 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

this notion has pretty much made the locking thermostat standard equipment in office buildings...


From what I understand, they're not even hooked up a lot of the time. They're just there to pacify people, to give them a small (but fake) sense of control.






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MikeBRLA
LSU Fan
Baton Rouge
Member since Jun 2005
9139 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

uh, wut ?


Pretty basic function of a standard home AC.

If it's on 80 (fan in the on mode) and say 80 outside then the compressor will not be on.... The air coming out of the vents will be roughly 80.

Then you turn the thermostat to 75, the compressor will then turn on (cooling the air coming across the coils) and thus cooler air will come out of the vents.

That's how ACs work.

Also, since it's a closed air system and can only cool the air X degrees from what is coming into the coils, lowing the thermostat will eventually lower the air coming INTO the coils, making the air exiting the vents colder than before when the ambient temp was warmer.

For example... say your system can only cool 15 degrees

90 in --->>> 75 out
80 in --->>> 65 out

Basic concepts of HVAC.




This post was edited on 6/5 at 7:49 pm


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tjohn deaux
LSU Fan
GA
Member since Feb 2007
6383 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

Posted by MikeBRLA


absolutely correct... beat me to it






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Breesus
New Orleans Saints Fan
House of the Rising Sun
Member since Jan 2010
24547 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

LINK



Someone on tiger droppings starts a thread asking a question about ceiling fans, some posted a link in response to a thread on ceiling fans that directs you to google searching the OP's question where the first search that comes up is the original thread where the question was asked, when this search option is clicked on it has a link in it that googles the question, which leads you to a link to the original thread asking a question about ceiling fans which has a link in it to google, asking the same question, which leads you to the thread that asked the question...



This post was edited on 6/5 at 7:57 pm


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Dpizz450
LSU Fan
Baton Rouge
Member since Jan 2011
4728 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

setting the thermostat lower makes the AC blow colder air.


That would be awesome.






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777Tiger
LSU Fan
Member since Mar 2011
10347 posts

re: Does a ceiling fan lower the ambient temperature of a room?


It actually draws energy in from the outside, making your compressor work harder/longer, and raising your utility bill.





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Spock's Eyebrow
LSU Fan
Member since May 2012
2874 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

If it's on 80 (fan in the on mode) and say 80 outside then the compressor will not be on.... The air coming out of the vents will be roughly 80.

Then you turn the thermostat to 75, the compressor will then turn on (cooling the air coming across the coils) and thus cooler air will come out of the vents.

That's how ACs work.


But putting the thermostat on 65 doesn't help you get from 80 to 75 any faster, which is the point...






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Napoleon
New Orleans Saints Fan
Member since Dec 2007
33816 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

MikeBRLA


Can I ask you a question?


Today I did a favor (I'm an appliance guy not an A/C guy I only have a Type I HVAC technician license)
The guy said he thought his fuse was bad. So I checked, good fuse. Then I checked the fan. Resistance was infinite. Hooked up a 230v test rig(just to appease the friend) and hooked the fan motor to it, with a 5uf capacitor. Nothing

So I replace the fan, and throw in a 5uf capacitor, rather than hooking it to the three way 50/5 uf capacitor on the unit. After installation (both browns to capacitor, white to common black to high voltage (black to black, white to red)
the new fan kicked on, the compressor appeared to kick on.

I figured job was done.
Well they just called saying it still isn't getting cool. So should I just replace the 50/5 capacitor, or should I take the unit back apart and check the resistance of the compressor?

I'm regretting not just replacing that capacitor as well.

I have red to common and yellow to the one that is not "fan"..

I'm just surprised it didn't work. The system has a good pressure, the evaporator fan is working, coils are clean.

I'm thinking go there with a $10 capacitor, and that will be it. But if it can be something bigger, than I', just going to call an A/C buddy.






This post was edited on 6/5 at 8:09 pm


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777Tiger
LSU Fan
Member since Mar 2011
10347 posts

re: Does a ceiling fan lower the ambient temperature of a room?


The compressor has only one setting, which is max cold. It runs until it meets the thermostat setting.





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Spock's Eyebrow
LSU Fan
Member since May 2012
2874 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

The compressor has only one setting, which is max cold. It runs until it meets the thermostat setting.


Exactly. It's either on or off.






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ruzil
Southeastern LA Fan
Baton Rouge
Member since Feb 2012
4477 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

Can I ask you a question?


Today I did a favor (I'm an appliance guy not an A/C guy I only have a Type I HVAC technician license)
The guy said he thought his fuse was bad. So I checked, good fuse. Then I checked the fan. Resistance was infinite. Hooked up a 230v test rig(just to appease the friend) and hooked the fan motor to it, with a 5uf capacitor. Nothing

So I replace the fan, and throw in a 5uf capacitor, rather than hooking it to the three way 50/5 uf capacitor on the unit. After installation (both browns to capacitor, white to common black to high voltage (black to black, white to red)
the new fan kicked on, the compressor appeared to kick on.

I figured job was done.
Well they just called saying it still isn't getting cool. So should I just replace the 50/5 capacitor, or should I take the unit back apart and check the resistance of the compressor?

I'm regretting not just replacing that capacitor as well.

I have red to common and yellow to the one that is not "fan"..

I'm just surprised it didn't work. The system has a good pressure, the evaporator fan is working, coils are clean.

I'm thinking go there with a $10 capacitor, and that will be it. But if it can be something bigger, than I', just going to call an A/C buddy.




Have you checked the flux capacitor. It needs precisely 1.21 gigawatts to function correctly. I'd check that first.






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lsu480
Arizona State Fan
Downtown Scottsdale
Member since Oct 2007
67145 posts
 Online 

re: Does a ceiling fan lower the ambient temperature of a room?


We just got a new AC unit last week and the guy said it would work better and actually save us money of we always used fan instead of auto.....do you agree with him?





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BananaHammock
LSU Fan
Californication
Member since Aug 2011
8423 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

stream 120 volts of electricity

1st semester circuits class (EE) would beg to differ on using the word stream to reference voltage. Voltage is a potential difference across two points or a reference to a source of energy. It is from this source of energy that current can flow from (depending on how you define negative electron flow, but that is another discussion for another thread). It is the current (amps) that is streaming into the room, not the voltage.

In mechanical terms, voltage is to pressure as current is to flow.

Figured some fellow nerdgineers would appreciate this discussion/clarification.







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The Goon
LSU Fan
Baton Rouge, LA
Member since Nov 2008
211 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

1st year Thermodynamic right there.


Heat transfer says that forced convection of a lower temperature over a hotter surface causes heat to mover from the warmer to the cooler. The fan causes your body to cool down and feel cooler.

The fan isn't there to cool the room, just make you feel more comfortable.






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Spock's Eyebrow
LSU Fan
Member since May 2012
2874 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

We just got a new AC unit last week and the guy said it would work better and actually save us money of we always used fan instead of auto.....do you agree with him?


Nope. In fact, that's really stupid advice.

Running the fan for much more than a minute after the compressor shuts off is just going to dump humidity back in the house. (Running for less than a minute does improve efficiency, and furnaces and/or thermostats can usually be configured to do this.)

If your ductwork is in the attic, running the fan will act as a heater because the air will pick up heat as it travels through the ducts.

If you have any kind of return/supply discrepancy, which can occur (say) when you close a door to a room that doesn't have a return or sufficient door undercut, the furnace fan is going to pull air from holes in the building's envelope, which means a mixture of attic and outside air. If this happens, the temperature and humidity will rise that much faster with the fan on all the time.

You should leave the fan on Auto and use ceiling fans on a room by room basis.






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KG6
LSU Fan
Member since Aug 2009
2175 posts

re: Does a ceiling fan lower the ambient temperature of a room?


(no message)


This post was edited on 8/15 at 11:18 am


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wallowinit
New Orleans Pelicans Fan
Louisiana
Member since Dec 2006
7208 posts

re: Does a ceiling fan lower the ambient temperature of a room?


I'm thinking start capacitor and I'm thinking it could cost up to $40 because I've changed those several times and that's around what it cost.

To be sure the compressor kicked in just hold your hand over the air coming from the fan and you should feel it getting warmer fairly quickly.






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Spankum
LSU Fan
Miss-sippi
Member since Jan 2007
31414 posts

re: Does a ceiling fan lower the ambient temperature of a room?


quote:

In mechanical terms, voltage is to pressure as current is to flow.


I know this...but I didn't know how much current a ceiling fan draws so I said volage...



This post was edited on 6/5 at 9:52 pm


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