I replaced my oil furnace last year with a heat pump and 96% eff. gas furnace, also had to remove oil tank and big furnace, it was $8300. In our current weather (30-48) it costs us $20 a month to heat and about $20 to cool in the summer. I replaced a 17 yr old trane High eff. air cond, for a Bryant, Fairly large unit but very efficient, Came with a 10year warranty , The warranty is awesome won't cost me a nickel for 10yrs. The heat pump is a dual speed right now is running on the low speed at 32 degrees. The thermostat is like a PDA, just about every parameter is user adjustable, from humidity to different temps at night, They call it the Evolution series, and brag it is the perfect heat system, For me the payback will be in 4yrs due to the extreme climate, should be quite a bit cheaper without the furnace for you. I think I went over all the brands in our area for two months , I think the top brands are Lennox, carrier,byant,trane. The ones to avoid completely are Coleman, armstrong,goodman. But then again they are more entry level priced. It's the same in that business --Find an installer thats good.