A heat pump can be a great way to reduce your energy costs, especially if you live in an area with mild winter temperatures. In addition to heating homes, these all-electric systems also provide space cooling in summer. Heat pumps transfer thermal energy in a process called the refrigeration cycle by drawing from the air, water or ground—even the sunlight that passes through windows—and using that heat to warm your home.
The basic Heat Pump has a single-speed compressor. Its output is on or off—there are no intermediate settings, and relative humidity swings up and down with the temperature. A more advanced system uses a variable-speed compressor to deliver just the right amount of heating or cooling, according to your needs. This approach is better at maintaining comfortable temperatures and controlling relative humidity than the yo-yo effect of single-speed units.
Whether you choose an air-to-air, geothermal or water-source model, your contractor should use a recognized load calculation method—such as ACCA’s Manual J—to ensure the system is correctly sized for your home. It’s particularly important to get this done if you have made major air-sealing or insulation improvements, which can affect how much heating and cooling the system produces.
Heat pumps can be a good fit in any kind of house, though they’re most commonly used in newer houses with ductwork. Larger models, often referred to as ducted heat pumps, have powerful compressors that take the place of a furnace and air conditioner in a central system. A smaller version of the ducted system, known as a ductless mini-split, has a single outdoor unit that connects to one or more wall-mounted indoor air handlers, or “heads,” that serve a room or group of rooms.
When choosing a heat pump, look for an energy efficiency rating of at least 13.0 SEER—that’s the current minimum requirement set by the federal Energy Star program. The higher the number, the more efficient the system is.
Most ducted heat pumps run on electricity generated by fossil fuels, but when they’re powered by renewable energy—like rooftop or community solar or by a green grid—they become even more ecofriendly. That’s why some states and utility companies offer rebates for this technology.
The primary refrigerants in heat pumps are hydrofluorocarbons, which can have a high global warming potential when they’re released into the atmosphere. That’s why it’s important to choose a contractor who understands the importance of properly handling and disposing of these chemicals. They should also make sure the coils are clean and free of debris, the system is charged with the correct refrigerant and there are no leaks or other mechanical problems. If you’re planning to install a heat pump, ask for referrals from family and friends and consider getting price quotes from several contractors. Those with experience with alternative energy can explain how the system works and answer any questions you might have. Then, have a qualified professional perform a load calculation and ductwork inspection before installing the system.