said by Mr Matt:Pandora, I was not able to find a comment in this thread regarding how various heat pumps operate while in the defrost mode. In my case when each heat pump goes into the defrost mode the compressor and heat strip operate together. My condensers and air handler fans draws a total of 41 and 45 Amps respectively at 240 Volts when in the defrost mode. The heat strip in each system is rated at 4.8 KW or 20 Amps at 240 Volts. A generator powering my 30,000 BTU heat pump in the defrost mode would have to supply 41 Amps or 9840 Watts and my 42,000 heat pump 45 Amps or 10,800 Watts. That total requirement would exceed the capacity of a 20,000 Watt generator which is why a load management system is required to use a 20,000 generator in my home. That is probably why one Generac dealer recommended a 36Kw generator for my home if I stayed all electric.
I agree with nunya that if you can use propane rather than electric heat strips for back up heat you can use a smaller generator and in my opinion your system will probably provide better quality heat. The key facts that one has to review is the total capital investment in you appliances for an all electric solution and the total capital investment for a propane/electric solution, along with the yearly operating cost and how long you plan to remain in this house. If the difference in cost is significant, I would also consider the convenience factor for the two different systems, to determine if the more expensive solution is better.
Good point, DLM will turn off any large appliance that draws too much off the generator. My understanding is I have 83 amps more or less stable from a 20KW generator.
We shall see what happens. It'll be interesting.
As to propane auxiliary heat, not going to happen, unless the electric bill is extremely high.