How much does furnace replacement cost in Seattle?

Repair or replace?

If your furnace is under about 15 years old and the repair is modest, repair usually makes sense. If it's older, needs a major part like a heat exchanger or inducer motor, or has needed several repairs in a row, replacement starts to win — especially when you factor in current heat pump incentives. We show both numbers so you can decide.

Many Seattle and Eastside furnaces installed in the 1990s and 2000s are now reaching the end of their service life. That's often the best time to consider a heat pump or dual-fuel system rather than a like-for-like furnace swap.

What drives the price

Main cost factors for a new furnace:

• Size — set by a load calculation, not the old furnace's label. Many older furnaces are oversized.
• Efficiency — high-efficiency condensing furnaces need PVC venting and a condensate drain.
• Staging — single-stage, two-stage and modulating furnaces differ in comfort, noise and price.
• Blower — variable-speed blowers improve comfort and filtration and cost more.
• Venting changes — moving from an old chimney vent to sidewall PVC venting adds work.
• Ductwork condition — sealing or fixing undersized returns improves performance.
• Gas line and electrical — sometimes need updating to code.
• Permits — mechanical permits are required for furnace replacement in Seattle and Eastside cities.

Should you consider a heat pump or dual-fuel instead?

A dual-fuel system pairs a heat pump with a gas furnace. The heat pump handles heating most of the year and all of the cooling; the furnace takes over only on the coldest days. For Puget Sound homes that already have gas and good ducts, it can be a practical middle path — you add cooling for summer heat waves and reduce gas use, while keeping familiar backup heat.

An all-electric heat pump can replace the furnace entirely. Whether that makes sense depends on your panel, ducts and goals. See our heat pump vs gas furnace guide for a deeper comparison.

How rebates change the net cost

Utility incentives can change the math more than any other line item. Seattle City Light and Puget Sound Energy both run heat pump incentive programs, and some Eastside cities add local programs on top. Eligibility depends on your utility, what you're replacing (gas, oil, electric resistance or an older heat pump) and the efficiency rating of the new equipment. We confirm what applies to your home during the estimate, show the price after incentives, and file the paperwork for you. Standard gas furnace replacements generally see fewer utility incentives than heat pumps, which is one reason we always price both.

How financing changes the monthly cost

Financing doesn't change the total cost, but it changes what you pay each month. Many homeowners compare the monthly payment on a high-efficiency system against the energy savings it delivers. Our payment estimator on the financing page gives you a rough monthly number, and actual terms depend on credit approval and the lender.

Permits in Seattle and the Eastside

Most HVAC replacements in the Puget Sound area need a mechanical permit, and many need an electrical permit too. Seattle permits run through the Seattle Department of Construction and Inspections (SDCI); Bellevue, Kirkland, Redmond and the other Eastside cities run their own permit desks, and some smaller jurisdictions use Washington's Department of Labor & Industries for electrical. Permit fees and inspection scheduling vary by city, so a quote that skips them isn't really comparable to one that includes them.

Puget Sound homes and furnace replacement

Furnaces in Seattle and Kent ramblers and split-levels often sit in crawlspaces, garages or tight utility closets. Access affects labor, and older installations sometimes need venting, gas line or condensate changes to meet current code. Homes that converted from oil decades ago may still have old supply runs or oversized ducts that never got rebalanced.

On the Eastside, many Bellevue, Sammamish and Redmond homes built from the 1980s through 2000s have furnaces in attics or garages with long duct runs to bonus rooms. A replacement is a good time to fix those weak rooms with better returns, zoning or a dedicated ductless head.

Ask whether a quote includes a load calculation, haul-away of the old unit, a new filter cabinet, thermostat setup and permits. Those line items explain much of the difference between two furnace quotes.