check to see what the cheapest fuel source is in you area. in my area its natural gas, second is oil, and last is electric heat(barring coal and wood). electric heat has always been the most expensive to use. as for a heat pump, they are only as good as the area they are installed in. meaning they are fantastic in arizona, or florida but not so good in new york or new jersey. they will always heat the building up to the right temp but that due to the back up electric heat kicking in. it is running on the same cost basis as your A/C. do you want an A/C bill all year round? a standard acceptable fuel bill is about $600 a season( a season being from nov to mar 5-6 mos). if your a/c - h/p is drawing $175 a month then you are looking at a seasonal heating bill of almost twice that. also, dont confuse efficiency with fuel cost per btu output.
heatpumps are designed for areas where the outdoor ambient temp is about 40 degr. at best. at this temp there is enough energy outside to pull in and heat up a home. once the temp gets lower than that then the electic backup heat kicks in. this is where you bills go up. geo thermal is a good method, but it may get pricy.
