cjt wrote:
Ed Pawlowski wrote:

"Art Todesco" wrote

http://www.nordyne.com/literature/8569%20Compr.pdf
The best would be to compare the electric meter with the unit running
and not running. This way you will have actual watt-hours and you
don't have to think of things like power factor, etc. But, it will
change depending on temperature. And the run time will vary when the
temperatures are cooler than when it is just plain hot outside.

Many electric bills give a 13 month use history. Mine even gives the
average temperature for the month. Look at months like April and
October when neither heat or AC is used much and compare to July and
August and you get a pretty good idea. Aside from that, the only
accurate method is a recording ammeter over time.



I think you mean a recording watt-meter. Amps don't account for power
factor.

Another question maybe you can help? If I buy a clamp on type ammeter
that plugs into my DMM to display the current... if my DMM measures AC
with true RMS, will that fix the problem of the power factor?