Heat pumps: repair, cost, and whether one fits your home

A heat pump is built like a central AC with one extra trick. An AC pulls heat out of your indoor air and dumps it outside. A heat pump does the same in summer, then reverses the flow of refrigerant in winter so it collects heat from outdoor air and releases it inside. A part called the reversing valve makes the switch.

Because it moves heat instead of burning fuel to create it, a heat pump can deliver more heat energy than the electricity it uses. ENERGY STAR describes this in its air-source heat pump guidance. The air coming out of the registers feels milder than furnace air, and the system runs for longer stretches. That is normal.

• Ducted air-source. The common whole-house setup. An outdoor unit pairs with an indoor air handler and uses your ducts.
• Ductless mini split. An outdoor unit feeds one or more wall or ceiling units. It suits homes without ducts, additions and problem rooms.
• Dual fuel. A heat pump paired with a gas furnace. The heat pump handles mild weather and the furnace takes over in deep cold.
• Geothermal. Uses buried pipe loops instead of outdoor air. It costs far more to install because of the ground work.

Most heat pump calls fall into a few groups: the system runs but the air is not warm, the outdoor unit is buried in ice, the thermostat shows auxiliary heat all the time, or the unit will not switch between heating and cooling. Some of these have simple causes you can check yourself, like a clogged filter, a tripped breaker or a thermostat setting. Others involve refrigerant, the reversing valve, the defrost controls or the compressor, and those need a licensed technician.

A heat pump works year-round, so it racks up more running hours than an AC that rests all winter. Regular filter changes and a yearly check matter more for that reason.

The installed price depends on the size of the system, the type, the efficiency level, the condition of your ducts and your electrical panel. The page on heat pump installation cost walks through each of those and what a quote should list.

A heat pump tends to fit well when you need both a new AC and a new heating system, when you heat with electric resistance, propane or oil, or when your winters are mild. In cold regions, look at cold-climate models and plan the backup heat carefully. If your current system is failing and you are unsure whether to fix it, the repair or replace calculator gives you a starting point before you ask for quotes.