Searching for furnace installation in Seattle? In an existing home, that job is a replacement: the old furnace comes out, the new one goes in on the same gas, venting, and duct connections — brought up to current code. We don’t handle new-construction installs. One crew handles the whole swap — removal, disposal, installation, permit, and commissioning — with one written price before the work starts.
What’s Included in a Furnace Replacement
1. In-home assessment
A tech visits the property, looks at the existing furnace, venting, and ductwork, checks the gas line and electrical, and measures the space. No commitment at this stage — it’s how we quote accurately.
5. Old furnace removal
We shut off and cap the gas line, disconnect venting and electrical, and haul the old furnace out for recycling. Disposal is part of the quote, not a separate charge.
2. Load calculation
We calculate the actual heating load for your house. Square footage alone gives the wrong answer — insulation, windows, and layout decide what size furnace the house needs.
6. Installation
New furnace set in place, gas connection made up and leak-tested, venting run (PVC for condensing models), condensate drain, ductwork transitions, and thermostat wiring.
3. Equipment recommendation
Based on the load calc, your home layout, and your budget, we recommend a specific furnace — usually two options: a solid 80% AFUE unit and a 95%+ condensing model, quoted side by side.
7. Commissioning
Once the furnace is in, we fire it, check gas pressure and temperature rise against the manufacturer’s spec, verify airflow at the registers, and set up the thermostat.
4. Permits
Every furnace replacement in King and Snohomish County requires a mechanical permit. We pull it. You don’t talk to the city — we do.
8. Inspection coordination
The city inspector comes out within a week or two of the install. We schedule it and meet them on site.
Why Fuse Service
Why Fuse Service for Furnace Replacement
Licensed, Factory-Trained Technicians
Every replacement is handled by our own licensed Washington techs — not a subcontractor. Gas connections, venting, and condensate are done to code and inspected.
Same-Day Availability
A dead furnace in January can’t wait a week for an estimate. We offer same-day in-home visits across King and Snohomish County when the schedule allows.
Up to 10-Year Parts & Labor Warranty
New furnace installations come with up to a 10-year parts and labor warranty. If something goes wrong after the swap, it’s on us, not on you.
Upfront Pricing — No Surprises
You’ll get a clear written estimate before any work begins. The quote covers removal, disposal, the new equipment, permit, and commissioning — one number.
What Affects Furnace Replacement Cost
Venting requirements
A 95%+ condensing furnace vents through PVC and drains condensate; an 80% unit uses a metal flue. Switching tiers can mean new venting runs — it’s in the quote, not a surprise later.
Single-stage, two-stage, or modulating
A single-stage furnace heats at one output. Two-stage and modulating units run quieter and hold temperature steadier, at a higher equipment price. The right choice depends on the house and how you use it.
Home size and load
A 1,200 sq ft cottage in Ballard and a 3,800 sq ft house in Sammamish need different equipment. The load calculation sizes the furnace to the house — not to whatever label the old one carried.
Efficiency tier
A baseline 80% AFUE unit and a 95%+ condensing model are priced differently — but the high-efficiency tier burns noticeably less gas every heating season.
Removal and disposal
Disconnecting the old furnace, capping the gas line safely, and hauling the unit for recycling are part of every replacement quote.
Thermostat and add-ons
A furnace swap is the cheapest moment to add a smart thermostat, media filter, or humidifier — the tech is already in the cabinet and the ductwork is open.
Ductwork condition
Existing ducts that are well-sealed and properly sized keep the swap simple. Older homes sometimes need a plenum rebuild or sealing work.
Permit fees and inspection
Bellevue, Kirkland, Redmond, Seattle, and unincorporated King County all have slightly different permit fees. We pull the permit and schedule the inspection — it’s included in the quote.
AC Brands We are Repair
We install the major furnace brands: Trane, Lennox, Carrier, Bryant, Rheem, Goodman, American Standard. Each tech is factory-trained on the systems we sell.
Areas We Serve
Fuse Service replaces furnaces across King and Snohomish County. Every job starts with an in-home visit — the estimate is based on your house, not a phone guess.
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