My house stays at 72 degrees all winter, no cold rooms.  it is an electric heat pump but it is getting its heat from a 62 degree source, not the outside air.   
My system cost $16,000 but I took a $4800 tax credit on that year's taxes.   
I also get all the domestic hot water I want.  Seriously I have tried to run it out of hot water, 2 showers and dishes at the same time.