Reader Contribution . The author’s air-source heat pump resembles an air conditioning unit, and it pictured here alongside one of the heating oil fuel tanks. Photos by Adam D. Bearup The following story covers our recent upgrade to an air-source heat pump, which works in conjunction with our fuel oil furnace. The efficiency of heat pumps has improved in recent years and most of our building projects that do not have access to natural gas now have propane forced-air furnaces with heat pumps instead. The heat pumps provide heat and can help to conserve propane. The heat pump that I am writing about is an air-source heat pump and it looks very similar to a conventional air conditioning condenser unit like those that sit outside of a house. According to the United States Department of Energy, “an air source heat pump can deliver one-and-a-half to three times more heat energy than the electrical energy it consumes”.