The essentials in 30 seconds
An air conditioner and an air-source heat pump use the same refrigeration cycle as a refrigerator: they move heat instead of making it. An AC only moves heat out of the house. A heat pump can also run in reverse and move heat from outdoors into the house in winter. ENERGY STAR says a ducted heat pump is like a central air conditioner that also works in reverse, and that in summer a central heat pump automatically becomes a central air conditioner. So in cooling there is no real difference; the question is heating. A heat pump can deliver up to three times more heat than the electricity it uses. If you have an older AC and a newer furnace, ENERGY STAR suggests a heat pump instead of a new AC, creating a dual-fuel system for a modest extra cost. In cold climates, choose a cold-climate model. The federal tax credit of up to $2,000 applied to installs through December 31, 2025, the IRS says.
- Sizing matters more than brand: ask for a Manual J load calculation.
- Utility rebates may still apply; check ENERGY STAR's rebate finder.
How each one works
- Air conditioner: moves heat from inside the house to the outdoors. In winter it does nothing; heating comes from a separate furnace or boiler.
- Heat pump: in summer, the same as an AC. In winter it reverses the flow: it extracts heat from the outdoor air and pumps it inside, as the DOE explains.
- Why it is efficient: it moves heat rather than converting fuel into heat, so it can deliver up to three times the heat energy of the electricity it consumes (ENERGY STAR).
Heat pump vs air conditioner
| Central air conditioner | Air-source heat pump | |
|---|---|---|
| Cooling | Yes | Yes, works as a central AC in summer |
| Heating | No; needs a furnace or boiler | Yes, by reversing the cycle |
| Ductwork | Uses the forced-air ducts | Uses the same ducts; ductless mini-splits exist |
| Efficiency labels | SEER2, EER2 | SEER2, EER2 for cooling; HSPF2 for heating |
| With a furnace | Separate systems | Can pair with a furnace (dual fuel) |
| Combustion | None (furnace aside) | None: no fuel storage, no on-site combustion emissions |
| Replacement | — | Often a drop-in replacement when the AC or furnace needs replacing |
SEER2, EER2 and HSPF2
SEER2 and EER2 rate cooling efficiency; HSPF2 rates heating efficiency, so only heat pumps have it. Higher is better. ENERGY STAR's current requirements for heat pumps are:
| Equipment | HSPF2 | SEER2 | EER2 |
|---|---|---|---|
| Split systems | ≥ 7.8 | ≥ 15.2 | ≥ 11.0 |
| Single package (incl. gas/electric package units) | ≥ 7.2 | ≥ 15.2 | ≥ 10.0 |
| Cold climate, ducted split | ≥ 8.1 | ≥ 15.2 | — |
| Cold climate, non-ducted split | ≥ 8.5 | ≥ 15.2 | — |
Cold-climate models must also show a COP of at least 1.75 at 5 °F and keep at least 70 % of their 47 °F heating capacity at 5 °F.
Do heat pumps work in cold climates?
Many new ENERGY STAR heat pumps provide space heating even in the coldest climates, thanks to advanced compressors and refrigerants, ENERGY STAR says. Cold-climate models are tested down to 5 °F; they keep working below that, but a backup heat source heats most efficiently in even lower temperatures. If winters regularly dip below freezing, ask the contractor for an ENERGY STAR cold-climate unit and whether you need backup heat.
Which should you install?
-
01
Old AC, new furnace
ENERGY STAR suggests replacing the AC with a heat pump for a modest extra cost and running dual fuel: heat pump or furnace, whichever is optimal.
-
02
AC and furnace both old
A heat pump can replace both, often as a drop-in on existing ducts; in cold areas, plan backup heat.
-
03
Oil, propane or electric resistance heat
The biggest savings: ENERGY STAR estimates about $950 a year switching from oil and $460 from electric resistance heaters, on average.
-
04
No ducts
Consider ductless mini-split heat pumps for part of the house.
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05
Size it right
Ask for a Manual J calculation; an oversized or undersized system struggles to keep you comfortable.
Tips once you have a heat pump
- Keep a steady temperature: heat pumps don't save energy by turning down while you sleep, ENERGY STAR says; the DOE advises avoiding changes of 3 °F or more.
- Use "Heat" in winter and "Cool" in summer, not Auto, which can switch modes on mild days.
- Start with Auto fan; continuous fan can hurt performance.
- Clean or change filters: about every 90 days on ducted systems, at least monthly on ductless, following the maker's instructions.
- If you keep an old furnace as backup, set its thermostat 2–4 degrees below the heat pump's.
Tax credits and rebates
The Energy Efficient Home Improvement Credit gave up to $2,000 a year for qualified heat pumps, but the IRS says it can be claimed for improvements made through December 31, 2025. Some ENERGY STAR pages still mention dates up to 2032; follow the IRS. Utility rebates may be available: ENERGY STAR's rebate finder lists them by ZIP code.
Heat pump vs air conditioner: FAQs
Is a heat pump the same as an air conditioner?
For cooling, yes: in summer a central heat pump works as a central AC. The difference is that it also reverses to heat the house in winter.
Does a heat pump cool as well as an AC?
Yes; both cool with the same refrigeration cycle, and ENERGY STAR heat pumps must meet SEER2 and EER2 cooling efficiency levels.
Is a heat pump more expensive than an AC?
ENERGY STAR says replacing a central AC with a heat pump usually costs a modest amount more, and the difference is paid back through lower energy bills.
Do I still need a furnace with a heat pump?
Not always. A properly sized heat pump can heat the home; in very cold climates a backup heat source is recommended, and many homes use dual fuel.
Is there still a federal tax credit for heat pumps?
According to the IRS, the Energy Efficient Home Improvement Credit covers improvements made through December 31, 2025.
Sources
Government sources, checked on 3 November 2026 (03/11/2026).
- ENERGY STAR · Air-source heat pumps ↗Up to 3× heat for the electricity used; like a central AC that also works in reverse; ducted or mini-split; drop-in replacement; Manual J sizing; dual fuel; cold climate tested to 5 °F with backup below; saving tips (steady temperature, no Auto mode, auto fan, filters). Read.
- ENERGY STAR · Air source heat pumps fact sheet (PDF, 2024) ↗Central ASHP becomes a central AC in summer; about $950 a year saved switching from oil, $460 from electric resistance; AC replaced by a heat pump for a modest additional cost; utility rebates. PDF read.
- ENERGY STAR · Heat pump equipment key product criteria ↗HSPF2, SEER2 and EER2 thresholds; cold-climate HSPF2; COP ≥1.75 at 5 °F; ≥70 % capacity at 5 °F vs 47 °F. Read.
- U.S. Department of Energy · Pump up your savings with heat pumps (30 May 2023) ↗Heat pumps transfer heat like a refrigerator; heat in winter, cool in summer; air-source most common; mini-splits for homes without ducts. Read.
- DOE / CEE · You installed an air source heat pump. Now what? (PDF) ↗Extracts heat from outside air in winter, works in reverse in summer; avoid 3 °F+ changes; Heat or Cool mode not Auto; auto fan; filters every 90 days ducted, monthly ductless; backup thermostat 2–4° below. PDF read.
- IRS · Energy Efficient Home Improvement Credit ↗30 % credit, up to $2,000 a year for qualified heat pumps; improvements made through December 31, 2025. Read.
Replacing an old AC?
Ask your contractor to quote a heat pump too, sized with Manual J; if you keep the furnace, you get dual fuel for a modest extra cost.