What is the fastest way to tell if I have a heat pump?
The fastest test is to set the thermostat to heat, raise the temperature a few degrees, and walk out to the outdoor unit. If the fan and compressor in that outdoor cabinet kick on and start blowing air, you have a heat pump, because a heat pump uses that same outdoor unit to pull heat into the house in winter. If the outdoor unit stays silent while warm air comes from the vents, your heating is coming from a furnace inside, and the outdoor box is only an air conditioner that runs in summer.
Do this test on a mild day, not in the middle of a heat wave, so you are not fighting the cooling season, and give it a minute for the system to respond. This one check settles it for most homes in under five minutes. If you want to double-check, the thermostat and the nameplate give you two more confirmations, covered below. Knowing which one you have changes how you maintain it, how you set the thermostat in a cold snap, and what it costs to replace, so it is worth being sure. If you are weighing the two for a future system, our heat pump vs air conditioner comparison lays out the tradeoffs.
Does my thermostat show whether I have a heat pump?
Yes. If your thermostat has an Emergency Heat setting (often labeled Em Heat or Aux Heat), you almost certainly have a heat pump, because only a heat pump has the electric backup heat that setting controls. A furnace-and-AC system has no such mode; it just switches between Heat, Cool, and Off. So a Heat / Cool / Off / Emergency Heat selection is one of the clearest signs of a heat pump on the wall inside your house.
Behind the wall, heat pump thermostats also use a wire on the O or B terminal, which drives the reversing valve that flips the system between heating and cooling. You do not need to open the thermostat to check this, and pulling one off its base is not necessary for identification. The Emergency Heat label on the front is enough. If your thermostat is a basic Heat / Cool / Off model with no backup-heat option, that points to a straight air conditioner paired with a furnace. Either way, if you are shopping for a smarter control, our best smart thermostats guide notes which models handle heat pump auxiliary heat correctly.
How can I tell if I have a heat pump from the outdoor unit?
A heat pump and an air conditioner look nearly identical from the outside, so the giveaways are behavior and one visible part. The behavior tell is season: a heat pump's outdoor unit runs in winter, an air conditioner's does not. If you have ever seen that outdoor box running, or steaming, on a cold day, it is a heat pump going through a normal defrost cycle to melt frost off its coil. An AC condenser is completely idle from fall through spring.
The visible part is the reversing valve, a brass cylinder a few inches long with a small solenoid coil on top, tucked among the copper lines inside the cabinet. Only a heat pump has one, because it is the component that reverses the refrigerant flow to heat instead of cool. You can often spot it by looking through the top grille or the side panel without removing anything. Two other soft clues: heat pumps are more often mounted on a raised stand or bracket so winter meltwater drains away, and both refrigerant lines running to the house may be insulated on some setups. None of these single clues is proof on its own, but together with the winter-running test they make it clear.
How do I tell from the nameplate or model number?
Check the data plate on the side of the outdoor unit and look for a heating efficiency rating. A heat pump lists an HSPF or HSPF2 number (heating seasonal performance factor) because it produces heat; a plain air conditioner lists only SEER, SEER2, and EER because it only cools. If you see an HSPF value anywhere on that sticker, it is a heat pump. This is the most reliable nameplate tell, because it does not depend on decoding a brand's model number.
Some plates also spell out the equipment type in words, and many model numbers carry a letter that flags a heat pump, though the exact code differs by manufacturer, so do not rely on the model number alone. The HSPF rating is the surest sign. While you are reading the plate, note the model and serial number anyway; you will want them for ordering parts or getting a replacement quote. If the rating language on the plate is unfamiliar, our what is a good SEER rating guide explains SEER, SEER2, and how the efficiency numbers translate to real performance.
Do I have a heat pump or a furnace doing the heating?
You have a heat pump if the outdoor unit is your source of heat, and a furnace if the heat is made indoors by burning fuel. The quickest way to separate the two is to look at your indoor equipment and utility connections. A gas or oil furnace has a burner, a flame, and a flue or vent pipe carrying combustion gases outside, and it connects to a gas line or an oil tank. A heat pump has none of that: no gas line, no combustion vent, no burner, just an indoor air handler with a blower and, usually, an electric backup heat strip.
It is also common to have both, which is called a dual-fuel or hybrid system: a heat pump for mild weather and a gas furnace that takes over in deep cold. In that setup the outdoor unit still runs in winter down to a changeover temperature, then the furnace kicks in. If you see a running outdoor unit in winter and a gas furnace indoors, you likely have a dual-fuel system. To understand how the two technologies compare on cost and comfort, see our heat pump vs furnace breakdown.
Why does it matter whether I have a heat pump?
It matters because a heat pump runs year round, so it needs different care and different thermostat habits than an AC. Because it heats and cools, a heat pump gets roughly twice the annual runtime of an AC and benefits from a filter change and a checkup before both the cooling and heating seasons. On the thermostat, the big rule is to avoid jumping the temperature several degrees at once in winter, since that triggers the expensive backup strip heat, and to leave the Emergency Heat setting alone unless the heat pump itself has failed. Our disadvantages of a heat pump guide covers the backup-heat trap in detail.
It also changes what you buy next. Replacing a heat pump means matching both its cooling and heating capacity to your home, not just its tonnage, so size a replacement with the BTU calculator before you take a quote rather than copying the old unit's size by default. If you have confirmed you have a heat pump and it is near the end of its life, our best heat pumps guide lists current picks with real SEER2 and HSPF2 numbers and cold-climate performance.
Frequently asked questions
What does a heat pump look like?
From the outside, a heat pump looks almost exactly like a central air conditioner: a square metal cabinet with a fan on top and a coil around the sides, sitting next to the house. The differences are subtle. A heat pump has a reversing valve (a small brass cylinder with a solenoid) inside the cabinet, it lists an HSPF rating on its nameplate, and it runs in winter. Indoors there is an air handler with a blower rather than a fuel-burning furnace.
Do I have a heat pump or a furnace?
If your heat comes from the outdoor unit and there is no gas line, burner, or flue pipe on the indoor equipment, you have a heat pump. If a unit indoors burns gas or oil, with a visible flame and a vent pipe to the outside, that is a furnace and the outdoor unit is just an air conditioner. Some homes have both, a dual-fuel system, where the heat pump handles mild weather and the furnace takes over in deep cold.
How do I tell if my AC is also a heat pump?
Set the thermostat to heat on a mild day and check whether the outdoor unit runs. A heat pump uses that outdoor unit to heat, so it will turn on; a plain air conditioner stays off in heat mode because a separate furnace does the heating. You can confirm it by checking the nameplate for an HSPF rating (only heat pumps have one) and the thermostat for an Emergency Heat setting.
How many years does a heat pump usually last?
A heat pump typically lasts about 10 to 15 years, a little less than a furnace or an AC that only runs one season, because a heat pump heats and cools and therefore runs close to year round. Regular filter changes, an annual checkup, and keeping the outdoor coil clear of leaves and snow all help it reach the top of that range. The compressor and reversing valve are the parts that drive the bigger repair bills if they fail.
Can I tell if I have a heat pump from my utility bill?
Sometimes. A home heated by a heat pump usually has no gas heating charge in winter and instead shows electric use that climbs sharply in the cold months. A home with a gas furnace shows a winter gas bill and a flatter electric bill. This is a hint, not proof, since electric furnaces and dual-fuel systems muddy the picture, so confirm with the outdoor-unit and thermostat checks.