Quick answer
Both machines move heat from inside your house to the outdoors in summer. An air conditioner can only push heat in that one direction. A heat pump adds a reversing valve, a defrost control, and a bit of engineering so it can pull heat from outdoor air and push it inside during winter. Cooling: identical. Heating: only one of them does it. Price: the heat pump costs more upfront — and it's the only one of the two that qualifies for Washington rebates.
- In cooling mode they're functionally identical — same efficiency classes, same comfort, same look.
- The heat pump's one extra trick: a reversing valve that turns it into your heating system too.
- If your AC and furnace are both aging, one heat pump can replace both — that's where the math gets interesting.
- WA HEAR and PSE rebates apply to heat pumps, not air conditioners.
Last updated: 2026-07-13 · Written & reviewed by the Eco field team
Heat pump vs AC at a glance
| Central Air Conditioner | Heat Pump | |
|---|---|---|
| Summer cooling | Yes | Yes — identical operation |
| Winter heating | No | Yes — 2–4 units of heat per unit of electricity |
| Key hardware | Compressor, coils, fan | Same, plus reversing valve + defrost controls |
| Pairs with | A furnace or air handler (something else must heat) | An air handler — or a furnace in a dual-fuel setup |
| Installed cost | Lower | Higher — but it's replacing two systems |
| Rebates (2026) | None | WA HEAR (income-qualified) + PSE |
| Runtime | Summer only | Year-round |
| Best fit | Furnace is new; you only need cooling | AC and heater both aging; electrifying; adding cooling + efficiency at once |
The decision usually hinges on your furnace
Furnace is newish (under ~10 years) and you just want summer cooling: a straight AC is the simpler, cheaper buy — no shame in it. Furnace is newish and you want cooling plus lower winter bills: consider a heat pump anyway — paired with your existing furnace as a dual-fuel system, it takes over most of the heating season and the furnace becomes your cold-snap backup. Furnace and AC are both aging: this is the clearest case — one heat pump replaces both, rebates soften the price, and you stop maintaining two systems. You heat with electric resistance: skip the AC conversation entirely — a heat pump cuts your heating energy dramatically and the cooling comes along free.
The Puget Sound angle
Cooling season here is short but no longer optional — the region's summers have changed, and AC went from luxury to expectation in about a decade. That's exactly what makes the AC-only purchase worth questioning: you'd be installing a machine that idles nine months a year, when the same box with a reversing valve could carry your whole winter. Mild PNW winters are prime heat pump territory, and current Washington rebate programs — HEAR for income-qualified households, plus PSE offerings — apply only to the heat pump side of this comparison. We confirm eligibility and handle the paperwork on every estimate.
Same machine, one extra valve
An air conditioner doesn't “make cold.” It absorbs heat from your indoor air into refrigerant, compresses it, and dumps it outside. A heat pump does exactly that in summer. In winter, the reversing valve flips the direction of the refrigerant flow, so the outdoor coil absorbs heat from outside air — which holds usable heat even on cold days — and releases it indoors. One valve, two seasons.
“If they're the same machine, why does the heat pump cost more?”
Fair question, and the honest answer has four parts. The reversing valve and defrost system add hardware. The unit gets engineered and warrantied for year-round duty instead of a three-month season. Heating capacity has to be sized to your home's winter load, not just its summer one — which takes a real load calculation, not a rule of thumb. And demand: the heat pump earns rebates and does two jobs, so it carries a premium. Whether that premium is worth it depends entirely on what's on the other side of your ductwork.
Pros and cons, honestly
Central air conditioner
Pros
- Lower installed cost
- Identical summer cooling performance
- The simpler buy when your furnace is new and you only need cooling
Cons
- Cools only — something else must heat your home
- Runs a single short season, then idles nine months a year
- No Washington rebates apply (2026)
Heat pump
Pros
- Identical cooling, plus 2–4 units of heat per unit of electricity in winter
- One system can replace an aging AC and furnace at once
- Qualifies for WA HEAR (income-qualified) and PSE rebates
- Year-round duty engineering and warranty
Cons
- Higher installed cost — though it's bidding on two jobs
- Needs a real winter load calculation, not a tonnage rule of thumb
The machine that idles nine months a year
An AC-only purchase installs equipment that runs one short season and sits idle the rest of the year, while the same box with a reversing valve could carry your whole winter. If your furnace is past mid-life, buying the AC now usually means paying for the same labor twice within a few years.
Missing the rebate window
Washington's current programs put money behind heat pumps and none behind straight air conditioners. Choosing the AC without running the side-by-side math can mean leaving thousands in HEAR and PSE incentives unclaimed — we quote both options against the same house so the real gap is visible.
The verdict, by situation
Straight AC
The simpler buy when your furnace is young
Furnace under ~10 years and healthy, and you only want summer cooling? A straight AC is cheaper and there's no shame in it — just know it idles nine months a year.
Heat pump
The clear winner when both systems are aging
One heat pump replaces the dying AC and the tired furnace at once, rebates soften the price, and you stop maintaining two systems. This is the strongest case in the comparison.
Dual-fuel
Heat pump + your existing furnace
Want cooling plus lower winter bills without retiring a healthy furnace? Pair them — the heat pump carries most of the season, the furnace becomes cold-snap backup.
Which Washington homes this fits
Furnace + AC both past mid-life
The clearest heat pump case: one system, one install, rebates behind it — and you stop paying for the same labor twice within a few years.
Newish furnace, first-time cooling
Price both: the straight AC is cheaper today, but the same box with a reversing valve could carry your whole winter as a dual-fuel system.
Electric-resistance heat, no AC
Skip the AC conversation entirely — a heat pump cuts heating energy dramatically and the cooling comes along free.
AC just died in August
The single best moment to consider a heat pump — labor, electrical, and refrigerant-line work overlap almost completely.
How we build this guidance
- We install both — straight ACs and heat pumps — across Seattle and Everett, and we'll tell you when the cheaper one is the right one.
- Sizing recommendations come from real load calculations on your house, not tonnage rules of thumb.
- Rebate guidance verified against current program sources, July 2026.
Methodology: Cooling equivalence reflects the shared refrigeration cycle and matching efficiency classes; heating efficiency stated as field-realistic COP ranges of 2–4 for modern cold-climate equipment in our climate.
Ready for the next step?
Get a free estimate for your actual house, not a hypothetical one — honest numbers and rebate eligibility checked before any work begins.
Continue exploring
- Learn: Furnace vs heat pump — which should heat your Puget Sound home? →
- Learn: How do heat pumps work? →
- Learn: When should I repair vs replace my AC in Washington? →
- Learn: Washington HVAC rebates explained →
- Evaluate: Heat pump vs gas furnace — which should heat your home? →
- Compare: Does a new heat pump add value to your home? →
- Compare: Furnace vs air handler →
- Learn: Cold-climate heat pumps vs standard models →
- Learn: Replacing baseboard heat with a heat pump →
- Cost: What heat pump installation costs near you →
- Book: AC and heat pump estimates →
- Learn: All Heating & Air guides →
Common questions
Does a heat pump cool as well as an air conditioner?
Yes — identically. In cooling mode a heat pump is an air conditioner, with the same efficiency ratings and the same comfort. Nothing about the reversing valve compromises summer performance.
Can I add a heat pump and keep my furnace?
Yes — that's a dual-fuel system. The heat pump handles most of the heating season efficiently, and the furnace steps in for cold snaps. It's a popular path for homes that aren't ready to leave gas entirely.
How much more does a heat pump cost than an AC?
The equipment premium is real but the honest comparison is system-level: an AC still needs something else to heat your home, while the heat pump is bidding on both jobs — and it's the only one that qualifies for Washington rebates. We quote them side by side so you see the actual gap for your house.
Do heat pumps wear out faster since they run year-round?
Not meaningfully — in our Puget Sound service experience both land in the same 10–12 year window with annual service. The heat pump logs more run-hours heating all winter, but mild summers go easy on it in cooling season, and modern units are built for year-round duty; maintenance moves the number more than the duty cycle does.
My AC just died. Should I replace it with a heat pump?
This is the single best moment to consider it — the labor, electrical, and refrigerant-line work overlap almost completely. If your furnace is also past mid-life, the combined replacement is usually the strongest value in this whole comparison.
Sources & references
Equipment ratings, program details, and industry figures on this page come from manufacturers and primary sources, linked below. Verify program status and requirements for your home where applicable.
Heat pump performance
- How air-source heat pumps move heat, and their efficiency advantage over electric resistance heating (roughly 50% less electricity) — US DOE Energy Saver — Heat Pump Systems
Washington rebates
- HEAR: income-qualified heat pump rebates administered by Washington State (funds first-come, first-served) — WA Dept. of Commerce — Home Electrification and Appliance Rebates (HEAR)
- Puget Sound Energy residential heat pump rebates — Puget Sound Energy — residential rebates
Equipment lifespan (our published data)
- Puget Sound service-life figures per Eco field experience: most HVAC equipment (furnaces, central ACs, heat pumps) runs 10–12 years with annual service — Eco — How Long Does an HVAC System Last in the PNW?