I'm a contractor and live in the hills over Malibu. I went through the same thing 2 years ago when I decided that the propane fired wall heater was not enough. A heat pump is basicly an airconditiong system running in reverse. I opted for the propane. If your house is well insulated the either will work. The propane might be cheaper depending on your electric rates. You can get a high efficiant propane system that can acctualy be vented with pvc. I dodn't like heat pumps there expensive to repair. Propane is the way I would go. just my 2cents