If you want to ditch your gas furnace and heat your home more cleanly and efficiently, you need to scale up one of your kitchen appliances. The first option is “electric resistance heating,” better known as a space heater, which acts like a giant toaster to warm a room instead of bread. The second is a heat pump, which extracts warmth from even freezing outdoor air and pumps it indoors, like a refrigerator moves heat from inside the box to the kitchen. (That’s why the back of your fridge feels warm, by the way.)

Energy experts say that to bring down greenhouse gas emissions and improve human health, we need to replace toxic gas furnaces and boilers with heat pumps ASAP.…