A: Where we live in Dover a generator is standard issue because we get frequent power outages in winter. However, no generator will produce enough power to run your heat pumps. This is one good reason to keep your fossil-fuel furnace when you add a heat pump. The back-up generator will run the circulating fans so the combination will keep you warm. I have recently bought a battery to replace my defunct back-up generator. The subsidies are very generous on batteries in MA right now, so if you are considering a back-up generator now is a good time to consider using a battery instead. Please see other answers on batteries.