The quickest way to tell the difference

The simplest test is to look at your outdoor unit in winter. If it runs when the temperature drops below 50°F, you have a heat pump. If it sits completely idle during cold months, you have an air conditioner. A heat pump moves heat from outside air into your home year-round; an air conditioner only cools.

You can also check your thermostat or equipment manual. If your system has a setting labeled "Heat," "Emergency Heat," or "Aux Heat," it is a heat pump. A standard air conditioner will have only "Cool" and "Off" (or "Fan Only"). Many homeowners discover what they own only when they need heating and realize their system cannot provide it.

Key Takeaways

  • Heat pumps run year-round to both cool and heat; air conditioners only cool and need a separate heating system.
  • Check your thermostat for a "Heat" setting—air conditioners have only "Cool" and "Off."
  • Watch your outdoor unit in winter; if it cycles on when it is cold, you own a heat pump.
  • Heat pumps cost more to install but lower heating bills; air conditioners are cheaper upfront but require a furnace or other heat source.
  • If you are unsure, your equipment manual or a technician can confirm which system you have in under five minutes.

What to look for on your thermostat

Your thermostat is the fastest way to know. Walk over to it and look at the mode selector or the menu options. A heat pump thermostat will show at least these choices: "Heat," "Cool," "Auto," and "Off." Some also display "Emergency Heat" or "Aux Heat" as a separate option. An air conditioner thermostat shows only "Cool," "Fan Only," and "Off"—no heating modes at all.

If your thermostat is digital or programmable, check the settings menu. Heat pump systems let you set different temperatures for heating and cooling. Air conditioner systems have no heating settings to configure. If you cannot find a heating mode anywhere on the device, you are almost certainly looking at an air conditioner paired with a furnace, boiler, or baseboard heater.

Signs in your outdoor unit during cold weather

In winter, stand outside and watch your outdoor unit for 10 to 15 minutes on a day when the temperature is below 50°F. If the fan cycles on and the unit makes noise, you have a heat pump extracting heat from the cold air. The unit may also have frost or ice on it—this is normal for heat pumps and means the defrost cycle is working. An air conditioner will not run at all during winter because there is no cooling demand.

Heat pumps are noisier in winter than in summer because they work harder to pull heat from cold air. You might also notice a brief pause or hear a hissing sound when the defrost cycle kicks in to melt ice off the coils. None of this happens with an air conditioner, which straightforward sits dormant until spring.

What your equipment manual or nameplate tells you

Every outdoor unit has a metal nameplate attached to the side or back. This label lists the model number, manufacturer, and system type. Look for the words "heat pump" printed on it. If the label says "air conditioner" or "cooling unit" only, that is your answer. The manual (if you have it) will also state the system type in the first few pages under "Product Description" or "System Overview."

If you do not have the manual, you can search the model number online. Type the model number into a search engine along with the manufacturer name, and the specifications will appear. Manufacturer websites and HVAC retailer sites both list whether a model is a heat pump or air conditioner. This takes five minutes and removes all doubt.

The difference in how they heat your home

A heat pump heats by moving warm air from outside into your home, even when it is cold outside. It uses the same outdoor unit and indoor coil for both heating and cooling. An air conditioner only cools; it cannot heat at all. If you have an air conditioner, your heat comes from a separate system—usually a furnace, boiler, heat strips, or baseboard heaters.

This matters because it affects your heating bills and comfort. Heat pumps are efficient at heating down to about 35°F. Below that, many heat pumps switch to "Emergency Heat" mode, which uses electric resistance heating and costs more to run. Air conditioners paired with furnaces use natural gas or oil, which may be cheaper or more expensive depending on your local utility rates. Knowing which you have helps you understand why your heating bills are what they are.

When to call a technician to confirm

If you have checked your thermostat, looked at your outdoor unit, and still cannot tell, a technician can confirm in under five minutes. They will look at the refrigerant lines, check the reversing valve (which heat pumps have and air conditioners do not), and verify the system type from the nameplate. This costs between $75 and $150 for a service call, but it removes guesswork if you are planning repairs or replacement.

You should also call a technician if your system is not heating or cooling properly. Sometimes a heat pump that appears broken is straightforward in defrost mode, or an air conditioner may have a refrigerant leak. A professional can diagnose the actual problem and tell you whether you need repair or replacement.

Why knowing matters for maintenance and repair

Heat pumps and air conditioners need different maintenance schedules and repairs. Heat pumps require more frequent filter changes because they run year-round. Both systems need annual coil cleaning and refrigerant checks, but heat pumps also need defrost cycle inspection in winter. If a technician arrives not knowing which system you have, they may waste time or recommend unnecessary work.

Knowing your system type also matters when you plan replacement. Heat pumps cost 20 to 40 percent more to install than air conditioners, but they lower heating bills in mild climates. Air conditioners are cheaper upfront but require a separate heating system. Understanding what you own helps you make informed decisions about upgrades and long-term costs.

Frequently Asked Questions

Can an air conditioner be converted to a heat pump?

No. An air conditioner lacks the reversing valve and other components needed to move heat in both directions. Upgrading requires replacing the entire outdoor unit and often the indoor coil. It is cheaper to repair an air conditioner or install a separate heating system than to convert it to a heat pump.

Why does my heat pump make noise in winter?

Heat pumps are noisier in winter because they work harder to extract heat from cold air. You may also hear hissing or a brief pause when the defrost cycle runs—this is normal and means the system is clearing ice from the outdoor coils. If the noise is unusually loud or accompanied by vibration, contact a technician.

What is Emergency Heat on my thermostat?

Emergency Heat (or Aux Heat) is a backup heating mode on heat pumps. It activates when outdoor temperatures drop below the heat pump's efficient range, usually around 35°F. It uses electric resistance heating, which costs more to run than the heat pump itself. You should not manually switch to Emergency Heat unless your heat pump stops working.

If I have an air conditioner, how do I heat my home?

Your heat comes from a separate system—a furnace, boiler, heat pump, or electric baseboard heaters. Check your basement, attic, or utility closet for a furnace or boiler. If you see only the outdoor air conditioning unit and no other heating equipment, ask a technician what heats your home, as some systems are hidden or less obvious.

How much does it cost to replace an air conditioner with a heat pump?

Heat pump installation typically costs 20 to 40 percent more than air conditioner installation, depending on your region and home size. Exact pricing varies by location, equipment brand, and whether ductwork needs modification. Contact local HVAC contractors for quotes specific to your situation.