Locally-owned since 1977 • Licensed, bonded and insured in Washington (WA Contractor Reg. #HOMECCA785BD) • NATE-certified technicians • Carrier Factory Authorized Dealer
HVAC replacement for Seattle-Tacoma homes
Home Comfort Alliance replaces whole heating and cooling systems (furnace and air conditioner, heat pump, dual fuel or ductless) for homeowners across the Seattle-Tacoma area and the wider Puget Sound region. Every replacement starts with a room-by-room load calculation (ACCA Manual J), and we pull the required permits. Replacement estimates are free, and you can see a price range first with our instant quote tool.
Signs it's time to replace your HVAC system
It is usually time to replace, not repair, when the system is older, repairs are getting more frequent, and comfort or bills are getting worse. Watch for:
- Repairs every season, or one large repair on an older system.
- Rising energy bills with no change in how you use the system.
- Rooms that never get warm or cool enough, or a house that feels damp or dusty.
- A furnace or AC that runs constantly or turns on and off in short bursts.
- New noises, burning smells or a yellow gas flame. If you smell gas, leave the home and call 911 or your gas utility from outside; PSE customers can call 1-888-225-5773.
Repair or replace: the $5,000 rule
A common rule of thumb: multiply the system's age by the repair cost. If the result is more than $5,000, replacing usually makes more sense than repairing. A 15-year-old furnace with a $400 repair scores $6,000, so replacement is worth pricing out.
The rule is a starting point, not a verdict. A repair visit starts with the $119 HVAC dispatch fee and a diagnostic, and our technicians tell you plainly when a repair is the better value. See heating and cooling repair.
What should you replace your old system with?
Replacing an HVAC system is the moment to choose the setup that fits your home best, not just to swap like for like. The four common choices in the Puget Sound area:
| System | Best for | What changes |
|---|---|---|
| Gas furnace and central AC | Homes with gas and ducts that want a familiar setup | New furnace and outdoor AC on the existing ducts |
| Heat pump (ducted) | Homes with ducts, especially all-electric homes | One outdoor unit heats and cools; electric air handler replaces the furnace |
| Dual fuel (hybrid) | Gas homes that want heat pump efficiency with gas backup | Heat pump plus gas furnace; the furnace runs on the coldest days |
| Ductless mini-split | Homes without ducts, or rooms the ducts do not reach | Wall-mounted indoor heads connected to an outdoor unit |
For most homes here, a heat pump or dual fuel system is the upgrade worth pricing: our mild winters suit heat pumps, they add air conditioning, and they qualify for utility rebates. Learn more about heat pump installation, furnace replacement and ductless systems.
What a replacement involves: sizing, ducts, electrical and permits
A good replacement is sized to your home, not to the old equipment. Many older systems were oversized, so we run a room-by-room load calculation (ACCA Manual J) on every installation. At the estimate we also check:
- Ductwork: leaks, undersized runs or damage that would limit a new system.
- Electrical: whether your panel has room for a heat pump or AC circuit; older or full 100-amp panels may need an electrical panel upgrade.
- Efficiency: new split AC systems must meet at least 13.4 SEER2 in the northern region, and heat pumps 14.3 SEER2 and 7.5 HSPF2, according to the U.S. Department of Energy.
- Permits: we pull the required mechanical and electrical permits.
How much does HVAC replacement cost in Seattle?
HVAC replacement in Seattle averages about $8,333, with most projects between $5,555 and $13,888, according to Angi's Seattle data (regional estimate, April 2026). Replacing a furnace and central air together runs $10,000 to $20,000 in Seattle, and a full system with new ductwork $15,000 and up. These are benchmarks, not Home Comfort Alliance prices.
| Benchmark | Cost | Source |
|---|---|---|
| Seattle average, HVAC replacement | $8,333 | Angi Seattle, April 2026 |
| Seattle typical range | $5,555 to $13,888 | Angi Seattle, April 2026 |
| Seattle, central air and furnace | $10,000 to $20,000 | Angi Seattle, April 2026 |
| National average | $7,500 ($5,000 to $12,500) | Angi national, August 2026 |
| Heat pump, national | $4,200 to $7,600 | Angi national, August 2026 |
Your price depends on your home's heating and cooling needs, the add-ons you need, how many rooms the system serves and where it's installed. Get a price range in about 30 seconds with our free instant quote tool, then a technician confirms the exact price on a free site visit.
Rebates for replacing your HVAC system (updated September 2026)
Utility rebates in the Puget Sound area go mainly to heat pumps, so choosing a heat pump or dual fuel system is how most homeowners lower the cost of a replacement. The federal 25C tax credit ended for equipment installed after December 31, 2025, according to the IRS.
| Utility | Heat pump incentive (September 2026) |
|---|---|
| PSE | $1,500 to switch from electric heat, plus a $2,400 Efficiency Boost if income-qualified; up to $4,000 to switch from natural gas |
| Tacoma Power | $1,000 to $2,000 rebates, plus 0% interest loans up to $20,000 over 7 years |
| Seattle City Light | Instant discounts of $300, $400 or $600 by efficiency tier; $2,000 to replace oil heat |
| Snohomish County PUD | $1,800 to $2,500 for qualifying ducted heat pumps |
Home Comfort Alliance is an approved contractor for PSE (Trade Ally), Tacoma Power, Seattle City Light, Snohomish PUD and Energy Smart Eastside. Eligibility rules are in our heat pump cost guide.
Paying for a new HVAC system: financing
Financing is available through Salal Credit Union and Synchrony, with low monthly payment plans starting at $179/month*, 0% interest options for qualifying customers and instant online approval. See financing options.
*Financing through Salal Credit Union or Synchrony, subject to credit approval. Rates, terms and monthly payments depend on the amount financed, the plan and your credit. 0% interest options are available to qualifying customers. See lender for full terms.
Get a free estimateAn in-home visit and a written, upfront price before any work begins.
Our HVAC replacement process
- Price range. Use the instant quote tool, then book a free in-home estimate by form or phone.
- Assessment. A comfort advisor runs the Manual J load calculation and checks your ducts, electrical panel, venting and equipment locations.
- Written options. Upfront, transparent pricing for each system choice, with rebates and financing.
- Permits. We pull the required mechanical and electrical permits.
- Removal and installation. NATE-certified technicians remove the old equipment and install the new system; our licensed electricians handle the electrical work.
- Startup. We test the whole system, set up the thermostat and walk you through it; the permit inspection follows.
What you get with Home Comfort Alliance
- Upfront, transparent pricing before any work begins.
- Free replacement estimates, with a price range first from our instant quote tool.
- A Manual J load calculation on every installation, and we pull the required permits.
- Approved contractor for PSE (Trade Ally), Tacoma Power, Seattle City Light, Snohomish PUD and Energy Smart Eastside.
- Carrier Factory Authorized Dealer, Mitsubishi Electric Diamond Dealer and Quilt dealer; we service all major brands.
- 1-year labor warranty on installations, and we support the manufacturer's warranty on covered parts.
- After-hours emergency service. Our phones are answered around the clock.
HVAC replacement FAQ
What is the $5,000 rule for HVAC?
Multiply the system's age by the repair cost. If the result is more than $5,000, replacement usually makes more sense than repair. It is a rule of thumb, so pair it with how the system is running and what a new one would save.
Should a 25-year-old furnace be replaced?
Usually, yes. A furnace that old is well past the age most systems are replaced, it is far less efficient than a new model, and parts get harder to find. Replacing it on your schedule is cheaper and safer than waiting for a midwinter failure.
Should I replace my furnace and AC at the same time?
Often, yes. The furnace blower and the AC coil work together, so replacing both keeps the system matched, and one installation visit and one set of permits covers both. If one part is much newer, we will tell you whether replacing only the other makes sense.
What is the cheapest time of year to replace HVAC?
Spring and fall, between the heating and cooling seasons. Angi reports savings of 10% to 15% on work booked outside the summer rush, and scheduling is easier than during a heat wave or cold snap.
Do I need new ductwork when I replace my HVAC?
Not usually. Most replacements reuse the existing ducts after we check them for leaks and sizing. If ducts are damaged or too small for the new system, we include the repairs in your written price.
Do I need a permit to replace my HVAC system in Washington?
Yes. HVAC replacement needs a mechanical permit from your city or county, and electrical work needs a permit from the city or WA L&I. Home Comfort Alliance pulls the required permits for every installation.
Are there rebates for replacing a furnace and AC?
Utility rebates in the Puget Sound area mostly go to heat pumps. Choosing a heat pump or dual fuel system is usually how you qualify; PSE, for example, pays up to $4,000 to switch from gas to a heat pump.
Sources: Angi (Seattle and national HVAC and AC cost data, April to August 2026), U.S. Department of Energy (2023 efficiency standards), IRS (25C credit), PSE, Tacoma Power, Seattle City Light, Snohomish County PUD and WA L&I, all checked September 2026.
Why Choose Home Comfort Alliance for Your HVAC Replacement?
Your Comfort is Our Promise
We promise...
Reliable heating, air conditioning, plumbing and electrical service, all from one trusted company.
To educate and guide you through your options so you’ll find the right solution at the right price.
Knowledgeable and respectful workers who ensure both your own comfort during the installation process, and lasting comfort from your home systems.
Outstanding service, communication, and follow-up, so your home is comfortable now and for years to come.
Get an HVAC replacement estimate
A comfort advisor will run your load calculation, compare system options and give you written pricing with rebates and financing at an in-home visit.
Get an estimate
A local comfort advisor will call you to set up your visit.