I would use hydronic water coil as back up. Put a 40000btu coil in front of the heat pump. Connect it to a 60000btu 90% efficient water and let the second stage heat call on the pump to circulate hot water to the coil. There will be no lag time in changing and you keep the efficiency of the heat pump as well. Works with any heat pump Use the highest efficient HP as possible. GEOthermo heating needs no back up in your area.
Originally posted by quickone
I live in Dallas, GA (nw GA) and about to replace the original 17 yo Ruud a/c unit and 3 ton furnace simultaneously. An American Standard owner/operator/installer is suggesting a duel-fuel heat pump w/variable speed blower/furnace. I hesitate to consider a heat pump only because we lived in an apartment 18 yrs ago with a heat pump that ran all of the time and never seemed to bring the heat up to a temp that was comfortable. I know technology has changed but is the added expense of the heat pump worth it and will it keep the house just as warm as a gas furnace? The A.S. owner tells me that there is an outside temp adjustment that can be made on the unit that kicks the gas furnace on at the preset temp (i.e. 20-30 F).