ANN ARBOR, MI – They put solar panels on the roof. They installed new windows and blew insulation into their walls. Then, they threw out their gas furnace. John Lofy and his wife, Laura Rubin, have ticked off a list of green updates to their 110-year-old home in a leafy Ann Arbor neighborhood. But going fully electric for their heating and cooling with a new heat pump, while a win for the environment, is one step that isn’t paying for itself.