It depends on where you live because:
1) Electricity rates vary dramatically across the continental US. Costs per kWH may be as low as 2 cents (Central Washington State) or has high as14 cents (New York City).
2) If your climate is moderate, an electric heat pump may be the lowest cost option as the primary source for heating and cooling.
Your local utility company or heating and air conditioning specialist should have information that will help you decide what is the best option to heat and cool your house.
-jtd
