Pete C. wrote:
Tony wrote:
Pete C. wrote:
Tony wrote:
I'm trying to figure the cost of running the central AC in my house.
Inside was fairly easy, a 1/2hp fan motor. Outside the numbers on the
plate from the factory are long gone. I found on the fan motor that it
is 1/8hp. Now the compressor.... On it is listed the voltage but not
the amps or watts but it does list the LRA (locked rotor amps) of 105.0
It is a Copeland CR38K6-PFV-370.

I found this site but even this isn't very useful to me only giving me
the RLA of 19. I read the RLA is "rated load amps" and does not mean
"Running Load Amps". RLA being the most current it should draw under
the harshest conditions.

http://www.nordyne.com/literature/8569%20Compr.pdf
None of those numbers are of much use in calculating operating costs
since none of those items runs 24x7. All those numbers will tell you is
how big a circuit the items require.
I've kept track a few times and during a hot 90F days with lows of 70F
it runs between 8 to 10 hours/day. That may be a low estimate, I'm
going to put a time meter on it for a much more accurate figure.

Depending on the system, even a run timer may not quite get you accurate
numbers. On my HVAC the air handler has a 90 second post run after the
compressor turns off in order to increase efficiency.

No delays here. Anyway that doesn't sound like it would increase
efficiency much, if any. I wouldn't like it blowing all that moisture
from the evaporator back into the house again as it warms up. If it's
cold when it turns off as it warms up it is still taking heat away from
what ever is around it. And if it doesn't cool off much in between
cycles, then it blows cooler air faster when it kicks on again.