On Thursday, July 24, 2014 1:42:35 PM UTC-4, Jeff Liebermann wrote:
On Thu, 24 Jul 2014 05:36:44 -0400, rickman wrote:



On 7/23/2014 11:22 PM, Jeff Liebermann wrote:

Probably a bit late...



From the current issue of Home Power magazine:

"Making the Most of Your Ceiling Fan"

http://www.homepower.com/articles/home-efficiency/electricity/making-most-your-ceiling-fan

The temperature of the motor was far higher than anything

else in the room, including windows exposed to direct sunlight.

Not only was the fan not cooling the people who weren�t in

the room, but it was also working as a little space heater.



Is this a joke article?



It's quite real. It's one of those short info articles that magazines

like to use for filler. I suspect that it might have been shortened

through over editing.



He lists some useful info and then draws faulty

conclusions.



I have to confess that I didn't read it thoroughly and criticially.

You're right. The article has problems.



I think the lead in line is a perfect example...



A ceiling fan can heat up to about 100�F when running



Wow! 100�F!!! That is pretty much nothing. The incandescent light

bulb in the same fixture is thousands of degrees and likely puts off

more heat.



Nope, they're about the same. A running ceiling fan will burn about

75 watts going full blast. A light bulb might burn about 75 watts.

Both convert most of the 75 watts into heat.

I don't think that's true in the case of the fan. A lot, hoefully most
of the energy is going into moving the air, not generating heat. It's like
saying 1 hp = 745 watts, so a 1 hp water pump is generating 745 watts in
heat. In fact, most of that energy is going to moving the water.
If it wasn't you'd have a resistance heater, not a pump.


It's the power

consumption in watts that's important, not the surface temperature. If

I place a sealing fan motor, and a light bulb, in two seperate

marginally insulated cardboard boxes, and let them run for a while,

the final temperature will be the same.


Per the above, I don't think so.




I think the case for the fan heating the room is a bit

overstated.



Yeah, probably true.



More useful would have been a simple statement of the

wattage of the fan. The comparison to the windows is totally absurd.



Yeah, also true.

Not really, because again most of the energy from the motor is
not resulting in heat. I made that mistake myself, suggesting that
you could measure the wattage using a Kill-a-Watt. You can measure it,
but you can't then say because it's pulling 50W that it's generating
50W of heat in the room.