I bought a 1700 sq. ft 60's rancher and am replacing the whole hvac system. The system in place now is from the 80's. I am closing the ridge vent and installing a power vent. I am spray foaming the attic roof and blowing in cellulose on the roof deck. gas makes me a little nervous because of lighting pilots and carbon monoxide. The price to switch from gas to a heat pump with installation of the electrical wire is about $1400. I am told my bills will be less with gas although the heat pump is more energy efficient. Should I stick with the gas and save $1400 upfront or change to heat pump. Both systems I am looking at are the 2 speed and compressor Trane 20xi. any thoughts?