Heat pump or Gas furnance?

You would never use the heat pump as secondary heating. They don't work well well when it's really cold. With that said, they may be better off just using the gas for heating. It's very dependent on the cost of gas and electricity.

I live in NC so we have much the same climate as VA. I have used both gas and electric/heat pump. I have found gas to be less expensive and more comfortable. There are still more variables, like do you have other gas appliances. I have a gas clothes dryer and gas stove. I have to pay $10 a month just to have them read my meter. Still I have found gas better on several levels, both cost and comfort. Plus I really hate electric ranges.

A "dual fuel" or "add-on" heat pump system works great. Heat pumps are more efficient and higher temperatures and furnaces are more efficient at colder temperatures. So this system utilizes both when they are at their peak efficiency.

Typically, an outdoor stat is used to switch between the two at a determined temperature (economic balance point) which also factors in the cost of the two fuels. You would not want to run the heat pump below the Thermal Balance Point as that is when the capacity is lower than the heat loss of your home.

If you would be getting central AC anyway, the minimal extra charge for a heat pump and controls are pretty small. Talk to a GOOD contractor for help. If the contractor seems hesitant to talk about the two, walk away as he/she are not trained or knowledgeable enough for my purposes. They have biases just like we all do.

It depends on whether his gas furnace was functioning or if he feared using gas. Gas has become more expensive than electric. Heat pumps will heat but it depends on severe temperatures. A geothermal heat is even better. He is only using his blower and his ductwork for his heat pump. I can understand him switching. Jo Ann

Depends on energy rates but in general heat pumps a cheaper especially if it has a high seer rating.