Hi,this is whisky4,what is the lowest outside tempature that a heatpump will work at and still be efficient,I was told by engineer that they will work down below 32 degrees,it's been lower then that in oakville,wa,about 10to20 degrees,can not get house above 50 degrees with heatpump and electric heat working makes me think that something is not working in the heating part of system,using fireplace not too efficient but works need to add a fireplace radiator to get heat out in the house,have not got too much experinece with fireplaces,working on right combination of wood,tried (fir,maple,cheery),but what will help more then anything will be to insulate walls and roof,changed windows already that helped a little,fireplace is in wrong place on wall more to to a corner then to center of room,thank,s whisky4

Sounds like part of your electric strip heat in the air handler is not working. If the heat pump failed the house should still be able to be heated with strait electric.