I dont know what your local utility rates are but I believe dual fuel is the way to go. Heat pumps often dont have the same life as a gas furnace and A/C combination because of the extreme conditions and length of operation (all winter in cold climates). Duel fuel offers the best of both worlds. If you are looking at the Bryant Evolution system you can easily set the change over point to gas heating from heat pump. I installed a Carrier Infinity duel fuel last October and I saved more on heating than cooling over my previous system.