Installing fans on gable vents?

[meirman]

In alt.home.repair on Mon, 14 Jul 2003 14:11:47 -0700 "Steve" posted:

How can it be both powered (spun) by the air flow and accelerating the air flow? Is it taking energy from the air or lending energy to the air?

If it were to do both, doesn't that sound like a perpetual motion machine?

Maybe turbines slow down the air less than ridge rails, and the only benefit of a turbine over a hole in the roof is that it keeps the rain out (while slowing the air down less than would be the case with say, a roof fan housing without the fan. Where the air has to go up, then sideways, and then up again.

Meirman

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[meirman]

In alt.home.repair on Wed, 16 Jul 2003 23:56:36 GMT 'nuther Bob posted:

If I were to do that in the late afternoon, most of the hot days it is still hotter outside than my house is inside.

If I didn't have the roof fan, it might be hotter inside, but it would be no less hot outside. So running the whole house fan would give me new air, but it would be very hot air. Other than AC, there would be no way to cool down the house until 10 PM or so when it was finally cool outside.

I'll bet. :)

With regard to time spent sleeping:

Another thing I do is I have a table fan on the window sill above my bed. Well, if it were a real table fan, I would have had to make a bracket or little shelf. This is a fan from some 30's to 60's machinery, I think, and it has a 4 or 5 inch square base.

I've added an external speed control, so I make it slow enough that I can't hear it, and

I've added an external thermostat, so if gets cool enough during the night, outside and then in the room, the fan turns off so that I don't get too cold.

Another thing I had a problem with was that I alwasys needed a cover, a sheet or a blanket no matter how hot it was. When I learned to sleep with no pajamas and no cover, it was like it was 10 degrees cooler.

Meirman

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[meirman]

In alt.home.repair on Tue, 15 Jul 2003 00:30:48 GMT "George E. Cawthon" posted:

P&M

With those numbers, the fan can run 22 hours a day for the cost of one hour of AC time. In fact my fan at max runs from 9 in the morning until 10 at night. Usually hours less.

Probably even less yet, now that I went two shades lighter on my shingles.

I don't have good numbers on my AC because I don't use it enough to know. I have a 1400 foot home plus bsement, and it runs about an hour the first time it is turned on, after being off for a day or more, and I don't know how much it runs during the rest of the day. but I have a roof fan. I'm sure it woudl run quite a bit more if I didn't.

Possible Anti-my-position arguments: 1) The fan removes air at 120 or

140 degrees, but may replace it with air that is 90 degrees plus, if that is the temperature outdoors. The AC... it has the same problem because the part outside also has to deal with 90 degree air which lowers the efficiency of the AC the hotter it is out. 2) moving air is harder than moving the gas in a pipe/liquid in the AC.

I'm not a conspiracy guy, and I generally think that most people are basically good. But if they can hide 100 billion dollars of receipts at Ahold company, and manipulate California oil prices and Enron statements and Arthur Anderson, I'm sure they can come up with reasons to say a roof fan isn't good when it is.

I would want some source other than the electric company.

And I don't know enough formulas or enough math or have enough data to know for sure. But I'm still convinced using a fan is more efficient

Meirman

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