which uses least energy?

Old 07-22-11, 07:21 AM
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which uses least energy?

We're in a 1200sq fit house. We have both these cooling systs:

a. nice heat pump

b. attic fan

Our attic fan is a pretty strong one. It does get the heat out pretty well.

We normally keep everything shut up, and set heat pump on 74degrees.

If we use the attic fan, we run it all day---probably 8 hrs. The heat pump comes on and goes off, depending on temps, etc.

In general, which syst use the least power? I'm thinking the heat pump, but thought I'd ask.
Old 07-22-11, 07:39 AM
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Get the Watts of each device (Attic Fan or heat pump compressor and fan) X number of hours X rate. = $
Old 07-22-11, 07:41 AM
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Well...w/o actually being able to measure them both...I'd have to bet the fan probably uses less over a 24 hr period. I'm only guessing with the figures I'll use

Your HP actually has 3 motors that are running, 2 fans and the compressor. And though it cycles, it's in use 24hrs a day. It may have a startup draw of 25 amps for everything...then drop to 8-10 for running some of that is 120V some is 220V(which would be double the actual power of a 120V circuit).

The attic fan depending on size and such of course...probably draws around 5-8 amps at startup and then drops to maybe 2 or less.

These would all need to be converted to watts to determine actual power used.

W/o knowing the steady state running draw...theirs no sure way to tell.

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