In summer a heat pump and a central air conditioner do exactly the same job in exactly the same way: they pull heat out of your house and dump it outside. The difference is a single component, the reversing valve, which lets a heat pump run the cycle backwards in winter and bring heat inside. That one part changes what you need to heat the house.
How each system works
An air conditioner circulates refrigerant between an indoor coil and an outdoor unit. The refrigerant absorbs heat indoors, the compressor raises its temperature, and the outdoor coil releases the heat outside. A heat pump has the same parts plus a reversing valve. In heat mode, the outdoor coil absorbs heat from the outdoor air (there is useful heat in air down to well below freezing) and the indoor coil releases it into the house.
Side-by-side comparison
| Heat pump | Air conditioner | |
|---|---|---|
| Cooling efficiency | Same SEER2 range | Same SEER2 range |
| Heating | Yes, 200–350% efficient | No, needs a furnace or boiler |
| Installed price (3 tons, reusing ducts) | about $10,000 – $20,000 | about $5,800 – $7,800 |
| Price premium for the same size and SEER2 | +$1,000 – $3,000 for the unit | – |
| Hours of use per year | Heating and cooling seasons | Cooling season only |
| Typical lifespan | 12–15 years | 12–17 years |
| Federal minimum efficiency | 14.3 SEER2, 7.5 HSPF2 | 13.4–14.3 SEER2 by region |
When a heat pump is the better buy
- You heat with electric baseboard, an electric furnace, propane or oil. The heat pump will cut heating costs sharply.
- Your furnace is old too. One heat pump replaces both units.
- You live in a mild or mixed climate (roughly south of Chicago), where a heat pump can handle the whole winter.
- You want to stop paying a gas connection fee.
When an air conditioner still makes sense
- You have a newer, efficient gas furnace and cheap gas.
- You live somewhere very hot where heating is rarely needed and you want the lowest upfront price.
Even then, many homeowners pick a heat pump and pair it with the existing furnace as a dual-fuel system. It adds flexibility for a modest premium and uses whichever heat source is cheaper at the moment.
Does a heat pump wear out faster?
It runs more hours per year, so its lifespan is a little shorter on average: about 12 to 15 years against 12 to 17 for an AC. Regular maintenance matters more for a heat pump for the same reason.
Costs to compare
See AC replacement cost and heat pump installation cost for full price tables, and the heat pump savings calculator for what the heating side would save you.