Heat Pump vs AC: What Is the Difference?

The short version

Both systems have an outdoor unit with a compressor and coil, an indoor coil, and refrigerant lines between them. In summer both pull heat out of your indoor air and release it outside. From the cooling side, you would not be able to tell them apart by comfort.

A heat pump adds a reversing valve and a few controls. In winter the valve sends refrigerant the other way, so the outdoor coil collects heat and the indoor coil releases it. ENERGY STAR notes that a central heat pump can use the ductwork already in your home and can often replace a central AC directly.

Side by side

Factor	Heat pump	Central AC
Cooling	Yes	Yes
Heating	Yes	No, needs a furnace or other heater
Efficiency ratings	SEER2 for cooling, HSPF2 for heating	SEER2 for cooling
Equipment price	Somewhat higher for a similar tier	Somewhat lower
Running hours	All year	Cooling season only
Extra parts	Reversing valve, defrost controls, backup heat	None of these
Outdoor unit in winter	Runs, frosts and defrosts	Sits idle

When a heat pump makes more sense

You heat with electric resistance, propane or oil and want lower heating bills.
Your furnace and AC are both near the end of their lives, so one system can replace two.
Your winters are mild, so the heat pump can carry most or all of the heating.
You have a gas furnace you want to keep as backup. A heat pump in place of the AC gives you a dual fuel system.

When a standard AC is enough

You have a fairly new, efficient gas furnace and inexpensive natural gas, and you have no plan to change how you heat.
You live where heating is rarely needed and the lowest purchase price matters most.
Your electrical panel has no room for backup heat strips and you would be relying on the heat pump alone.

Even in these cases, ask for a heat pump price alongside the AC price. The gap between the two is often smaller than people expect, and the heat pump gives you a second way to heat the house.

Things to check before you choose

Sizing. Either system should be sized from a load calculation. In cold regions the heating load may call for a different size than the cooling load, and the installer has to balance the two.

The indoor unit. A heat pump has to be matched with a compatible indoor coil or air handler. If you are keeping an existing furnace, confirm the match and the thermostat wiring.

Wear. A heat pump runs in every season, so it logs more hours per year than an AC. Regular filter changes and periodic service matter more.

Replacement timing. If your current AC is failing, the page on AC replacement cost covers what a new AC involves, and the heat pump overview covers the heat pump side so you can compare quotes for both.

Common questions

Is a heat pump an air conditioner?

In cooling mode, yes. It uses the same parts and the same process as a central air conditioner. A heat pump is an air conditioner that can also run in reverse to heat the house, which a standard AC cannot do.

Does a heat pump cool as well as central air?

Yes. At the same size and SEER2 rating, a heat pump and a central AC cool equally well and use about the same electricity doing it. Cooling comfort depends far more on correct sizing, duct condition and installation quality than on which of the two you pick.

Does a heat pump cost more than an air conditioner?

The equipment usually costs somewhat more than an AC of the same size and efficiency tier, because of the reversing valve and added controls. Installation labor is similar. If the heat pump also replaces a furnace, compare it against the cost of both an AC and a furnace.

Can I replace my central AC with a heat pump and keep my furnace?

Yes, in most homes. The heat pump takes the place of the AC outdoor unit and coil, and the furnace stays as the air mover and backup heat. This is a dual fuel setup. The installer needs to confirm the coil match, the thermostat and the control wiring.

Sources

ENERGY STAR: Air-Source Heat Pumps

Heat pump vs air conditioner