Adding cooling: central AC or a heat pump?
As cooling machines they're the same hardware — a heat pump is an AC with a reversing valve. This guide walks the decision framework: furnace age, how long you'll stay, rebate eligibility on your utility territory (Seattle City Light instant discounts vs PSE conversion or hybrid rebates), and whether you're hedging PSE gas-rate escalation. The side-by-side comparison table on our compare page is for when you already want column specs — use this page when you're still deciding which path fits your house. Straight AC costs less upfront when the furnace is staying; a heat pump replaces most of that furnace's job, unlocks utility rebates, and changes your winter fuel math.
The quick answer
- Cooling performance: identical hardware, identical comfort — this axis is a tie
- Straight AC: lower upfront cost, zero rebates, leaves your heating untouched
- Heat pump: heats too, SCL/PSE rebate-eligible, pairs with your furnace as dual-fuel
- The furnace's age is the real decision input
When straight AC is the right buy
Your furnace is under ~10 years old and healthy, the budget is firm, and you want the summer problem solved without touching the heating that already works. AC added to a good ducted furnace is the cheapest path to whole-home cooling — and there's no shame in solving one problem at a time.
This path is especially defensible in PSE gas territory when your panel is already spoken for (EV charger, induction range, tankless electric on the horizon) and you're not ready to electrify heating yet. A straight AC install avoids the electrical-scope conversation while your newer furnace keeps doing what it does well through Seattle's long shoulder seasons.
When the heat pump premium pays
Your furnace is mid-life or beyond (buy one outdoor unit instead of AC now plus a furnace in five years), your heating is electric-resistance or oil (the savings are dramatic and the rebates largest — PSE electric-conversion $1,500–$2,400; Seattle Clean Heat $2,000–$6,000 for oil), or you're hedging PSE gas-rate escalation (+9.4% in 2025, more in 2026, per the WA UTC).
The dual-fuel middle: heat pump as primary with your existing gas furnace as cold-snap backup — PSE pays a hybrid rebate ($1,500/$2,400) and your newer furnace keeps a job. This is often the right answer for the 5–10-year-old-furnace house that wants cooling.
Stay horizon closes the loop: if you're in the home five-plus years on SCL electric or PSE gas, the heat pump path amortizes rebates and shoulder-season efficiency; if you're moving in two, straight AC plus a sound furnace may be the rational buy — just don't let sticker price alone make that call without writing down both timelines.
What does it cost in the Seattle area?
Installed market ranges for the two paths (before any rebates):
Central AC installation
$5,100 – $9,800 typical ~$7,400
New central air conditioner added to an existing furnace/ductwork
Sources: Angi — AC replacement cost, Seattle WA (2025–2026) · HVAC Project Cost — Seattle, WA (2026)
Ducted heat pump installation
$8,000 – $16,000 typical ~$10,200
All-electric heating + cooling using your existing ductwork
Sources: HVAC Project Cost — Seattle, WA (citing Angi 2026) (2026) · WattFax — 113 WA homeowner quotes (2026)
- Rebates apply to the heat pump column only — SCL instant discounts or PSE conversion/hybrid rebates
- Both paths depend on furnace blower and duct condition; corrections add to either
- Heat pumps may need panel/electrical work in older homes — get it answered in the bid
- Equipment tier (staging, variable speed) moves both ranges similarly
These are typical Seattle-area market ranges compiled from published cost guides (Angi, HomeGuide, and Seattle-area 2025–2026 cost studies) — market context, not a quote from Glendale Heating & Air Conditioning. Your home's size, equipment, ductwork, electrical, and permits change the number. National figures are marked; Seattle-area labor typically runs above national averages.
The honest trade-offs
Central AC (keep furnace heating)
- Lowest upfront cost to whole-home cooling
- No electrical-panel implications in most homes
- Heating system untouched
- No utility rebates
- You'll still replace the furnace on its own clock
- Fully exposed to gas-rate escalation
Heat pump (cooling + primary heating)
- One machine covers summer and most of winter
- SCL/PSE rebate-eligible
- Hedges gas rates; pairs as dual-fuel with a good furnace
- Higher upfront cost
- May trigger panel or wiring work in older homes
- Heating savings vs newer gas equipment are modest at today's rates
Where this decision goes wrong
Deciding by sticker price alone — the AC-now bid that ignores the furnace's age buys the same outdoor-unit work twice within a decade. Deciding by slogan ('heat pumps are the future' / 'heat pumps don't work here') instead of your house's actual heating, panel, and timeline. And letting either bid skip the load calculation: oversized cooling short-cycles and leaves the house clammy regardless of which machine you chose.
Utility-territory confusion is its own failure mode: SCL customers price instant equipment discounts at purchase; PSE customers file conversion rebates after install with network-qualified contractors. A bidder who quotes 'the rebate' without naming your utility and program is guessing. Pre-war Seattle homes on 100-amp panels also get steered wrong when nobody prices the electrical answer alongside the equipment — ductless or right-sized ducted heat pumps often fit where oversized ducted setups with strip backup won't.
Housing-stock blind spots finish the list: Eastside homes with tight ducts may need sealing before either path performs; no-duct Wallingford bungalows sometimes discover the AC-vs-heat-pump question was always a ductless-vs-ducted question in disguise. Run the retrofit framework before treating this as a straight equipment swap.
A bidder who hands you the comparison table without walking furnace age, stay horizon, and utility territory hasn't finished the framework — sticker price is the last cell, not the first.
Questions Seattle homeowners ask
Do heat pumps cool as well as dedicated AC?
Yes — in cooling mode they are the same machine. SEER2 ratings, comfort, and dehumidification behave identically for equivalent tiers. Every difference between the paths lives on the heating side.
How much more does the heat pump path cost?
Before rebates, the sourced Seattle ranges overlap: AC installs run $5,100–$9,800 and ducted heat pumps $8,000–$16,000, with equipment tier and home specifics driving position. Rebates narrow the gap — up to $600 instant from SCL, or $1,500–$4,000 from PSE when the heat pump displaces electric or gas heat.
My furnace is only five years old. Doesn't that settle it for AC?
It makes straight AC very defensible — but check the dual-fuel option before deciding: a heat pump in the AC slot with your furnace as backup gets you rebate eligibility and shoulder-season efficiency while the furnace keeps its job. The delta over straight AC, after the hybrid rebate, is the number to look at. On PSE gas with a five-year stay horizon, dual-fuel often beats straight AC even when the furnace is young — on a two-year timeline, AC alone is rational.
Does either path require duct changes?
Both use your existing ducts and both inherit their condition — a duct check belongs in either bid (WA code brings testing into play at replacement, with ~15% leakage as the action threshold). If ducts are marginal, sealing improves whichever machine you buy. Pre-war homes with inaccessible flex runs sometimes discover duct work pushes the decision toward ductless even when a furnace-and-AC mental model was the starting point.
Continue exploring
How we know this
Hardware equivalence per standard split-system design; ranges from published Seattle-area cost studies (2025–2026); rebate terms verified July 2026 (seattle.gov, pse.com); rate trajectory per WA UTC orders.
Reviewed by the Glendale Heating & Air Conditioning team · Last updated 2026-07-15
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