I'm in the process of looking at replacing an old AC unit and natural gas furnace that have seen better days. They both work, I'd just like to get more efficient units. I live in the Tacoma area and electric rates are $0.066/KWH and gas is roughly a $1/therm. My electric usage is about 500KWh/month and gas usage is 1.7 Therm/day on average. I have a 4000 sq foot house with a basement. I have installed a solar hot water heater which definitely helps. I just got a quote for an American Standard Hybrid System (Heritage 16 Heat Pump, 95-2 Stage Variable Furnace, indoor comfort coil, accuclean filtering system, Honeywell Focus Pro wireless thermostat, and whole house duct cleaning and sanitation) for about $18000 (that's with tax). Not sure if I should pull the trigger....kinda pricey. My questions are the following 1. Is this a good deal? 2. Would it make more sense (given my moderate climate conditions) to forego the furnace and just stick with the heat pump and use heat strips for auxiliary heat? 3. Or would it make better sense to stick with the heat furnace and invest in a high efficiency air conditioner? 4. Or should I simply get an energy audit and invest more heavily in efficiency retrofits for my house?

Any suggestions would be appreciated!