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# which uses least energy?

## which uses least energy?

#1
07-22-11, 07:21 AM
Member
Join Date: Nov 2004
Location: xxx
Posts: 308
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.

#2
07-22-11, 07:39 AM
Member
Join Date: Aug 2008
Location: Texas, California
Posts: 1,411
Get the Watts of each device (Attic Fan or heat pump compressor and fan) X number of hours X rate. = \$

#3
07-22-11, 07:41 AM
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 19,281
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.