Should it , or should it not 'automatically' go on to the gas furnace when the heat pump is not satisfying the thermostat? I'm in a house that's not insulated, (soon to be, problem will probably go away) and with the thermostat on 76 and the outside temp at about 40, it was not able to bring the room above 72. I kept thinking it should kick in the furnace. I have a call in to my installer, and he was going to investigate it a bit. He was on a ladder at the time and not sure of the answer. I'm thinking this would almost have to be a function of the thermostat, as the heat pump logic would not know the room temperature. OR does it? The thermostat is the WR comfort set 90 model 1F95-377 . thanks for any input..