Quick answer
Replacing AC alone makes sense when your furnace is young and sound — but if both are aging, a heat pump replacement often qualifies for rebates and eliminates a separate cooling unit.
- Compare practical options by risk, cost range, and comfort outcome.
- Identify what to verify in an estimate before you sign.
- Choose a path that fits your budget and timeline.
Summer failure
AC died during a heat wave and you're choosing like-for-like vs upgrade.
Compare your options
Like-for-like AC
Lower upfront when furnace is new; match SEER2 to budget.
Heat pump crossover
Replace both functions; stack rebates; plan for electrification.
Key terms and context
This guide is written for heating & air decisions in the Puget Sound. It uses the same terminology you'll hear from inspectors, technicians, and permit offices.
Mismatching with old furnace
New high-SEER AC on ancient furnace may not deliver rated efficiency.
How we build this guidance
- Straight answers first, so you know your options without the fluff.
- Written and reviewed by techs who do this work every day.
- Specific to Puget Sound homes, weather, and utilities.
- Updated 2026-06-08 from real heating & air jobs around the region.
Methodology: Equipment tiers from Eco catalog; rebates verified at estimate.
Last updated: 2026-06-08
Ready for the next step?
Get a free, no-obligation estimate from Eco — honest range before any work begins.
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Common questions
Best time to replace?
Spring before cooling season — better scheduling and pre-summer pricing.