I HAVE OWNED A PROPANE GAS FURNACE FOR THE LAST 10 YRS. I RECENTLY CONVERTED TO HEAT PUMP W/ELECTRIC SUPP. HEAT. MY ELECTRIC BILL HAS GONE UP 10% BUT MY PROPANE BILL IS ALMOST NONE ( GAS STOVE ). I WOULD RECOMMEND A HEAT PUMP. I LIVE IN NORTH TEXAS. TEMPATURES IN WINTER TIME ARE BETWEEN 15 & 40 DEGREES.