Which permit a Seattle heating job needs
SDCI's Furnace & Refrigeration FAQ and Mechanical Permit page (read 23 October 2026) split the work like this:
| Job | Permit | Who can apply | Issued by |
|---|---|---|---|
| Furnace replacement or alteration | Furnace or mechanical STFI permit | Contractor or homeowner | SDCI |
| Split-system heat pump or AC, or any job with refrigerant piping | Refrigeration permit (as well) | Licensed refrigeration contractor only | SDCI |
| Gas piping to the furnace | Gas piping permit | Licensed gas piper | Public Health – Seattle & King County |
| New circuit or electric furnace wiring | Electrical permit | Electrician or owner-occupant | SDCI |
The mechanical permit itself "does not enable you to install plumbing, sprinklers, gas lines, refrigeration, and boiler pressure vessels; these all require a separate permit." In Seattle, plumbing and gas piping permits come from Public Health – Seattle & King County, not the City. Replacing a gas furnace with a heat pump moves the job onto the refrigeration track; see the Seattle heat pump permit.
What it costs
Table D-8 of SDCI's 2026 Fee Subtitle (effective 1 January 2026, read 23 October 2026):
| Item | 2026 fee |
|---|---|
| Forced-air, gravity or floor furnace, heat pump, wall furnace, recessed wall heater, woodstove or fireplace insert, "including ducts and burners attached thereto" | $60.35 per unit |
| New gas or oil burner | $75.50 per unit |
| Appliance vent (Class A, B, BW or L) installed separately | $59.85 per unit |
| Renewing or re-establishing a furnace permit | ¼ of the base fee |
| Adding work or changing information on an issued permit | ¼ of the base fee |
| Technology fee | 5% of all fees |
The fee is charged "for each furnace if it is applied for without plans"; a furnace inside a larger mechanical permit with plans carries no separate fee.
Who can pull it, and how
SDCI: "You can get a furnace or mechanical STFI permit as a homeowner." In the Seattle Services Portal, choose Create New, Permits-Trade, Construction, and Land Use, Trade Permits, then Furnace or Mechanical STFI; a homeowner doing the work ticks the homeowner affidavit checkbox, and a mechanical STFI permit needs drawings attached.
Inspections, per the same FAQ:
- Cover inspection for furnaces and duct systems "once they have been 'roughed in' but before any part of the system is covered".
- Final inspection once the installation is complete.
Book in the portal under Inspections and Appointments. Before 7:00 a.m. means same day; for a two-to-four-hour window, call your inspector between 7:00 and 8:00 a.m. via (206) 684-8950. Results are in the portal's Inspections Review Report.
What 18,668 Seattle furnace and heating permits show
| Measure | Seattle furnace and heating |
|---|---|
| Permits on homes, October 2023 to September 2026 | 18,668 |
| Firms | 316 |
| Usual filed value | $7,550 |
| Middle half of firms' usual value | $6,500 to $14,000 |
| Completed (permits a year or more old) | 86.2% |
| Usual days from issue to completion | 66 |
| 10th / 90th-percentile firm (10+ permits) | 69.1% / 97.2% |
| Share held by the five busiest firms | 32.4% |
| Busiest / quietest month | October (index 130) / August (87) |
Furnace work in Seattle is seasonal in the obvious direction: filings peak in October and bottom out in August, so a replacement you can plan is easier to book in late summer. It is also concentrated: the busiest firm, Greenwood Htng & Home Services, filed 901 in the last 12 months. 13 of the 119 firms with 10 or more permits completed fewer than 70%. Values by job size are on the Seattle HVAC cost page.
See every Seattle furnace and heating contractor by permits completed →
Related
Heat pump or furnace: heat pump vs furnace in Seattle. Choosing the installer: hiring an HVAC contractor in Seattle. Other cities' rules: do I need a permit for HVAC replacement. Prices: HVAC replacement cost. Seattle counts by month: Seattle permit statistics. Licenses: Seattle contractor license lookup.
What this does not tell you
Our furnace and heating category is SDCI trade permits for heating equipment; gas piping permits from Public Health are not in it. Homeowner permits name no firm. License status is our name match to L&I, not SDCI's trade licenses.
How we know this
Permit types, the homeowner rule and inspection steps are quoted from SDCI's Furnace & Refrigeration Permits & Inspections FAQ and Mechanical Permit page, and fees from Table D-8 of SDCI's 2026 Fee Subtitle, all read 23 October 2026. Counts are SDCI trade permits on Seattle homes in our Furnace & Heating category, October 2023 to September 2026; "completed" uses permits a year or more old marked completed or closed.
Numbers come from City of Seattle (SDCI) building, trade and electrical permits on single-family and duplex homes (the city's open-data exports), data through October 17, 2026. Nobody paid to be on this page and nobody can.
Questions
- Do I need a permit to replace a furnace in Seattle?
Yes. SDCI says 'You need a permit for any furnace replacement or alteration', usually a furnace permit or a mechanical subject-to-field-inspection (STFI) permit from the Seattle Services Portal.
- How much is a furnace permit in Seattle?
SDCI's 2026 Fee Subtitle charges $60.35 per unit for a forced-air furnace, heat pump, wall furnace, woodstove insert and similar heating equipment, plus a 5% technology fee. Renewing a furnace permit costs a quarter of the base fee.
- Can a homeowner pull a furnace permit in Seattle?
Yes. SDCI says 'You can get a furnace or mechanical STFI permit as a homeowner'; tick the homeowner affidavit box in the portal. A split-system heat pump or air conditioner also needs a refrigeration permit, which only a licensed refrigeration contractor can get.
- What inspections does a Seattle furnace permit need?
A cover inspection once the furnace and ducts are roughed in, before anything is covered, and a final inspection when the install is done. Inspections booked before 7:00 a.m. happen the same day.
- How long does a furnace permit take to close in Seattle?
The usual Seattle furnace and heating permit in our file was completed 66 days after issue, and 86.2% of those a year or more old were completed.
Build your own list
Every firm with that kind of permit on record. Pick what you value. The list moves.
Related guides
- Washington's 2024 building and energy codes take effect 3 May 2027: what changes for new homes, additions and AC replacements
- Ames building permit search: how to look up permits on an address
- Do I need an HVAC permit in Ames? Yes: what is exempt, homeowner permits, the $56.23 base fee and inspections
- Do I need an HVAC permit in Anaheim? The mechanical permit for a furnace or AC change-out, fees and inspections
For one city
- Furnace & Refrigeration Permits & Inspections FAQ — SDCI (accessed 2026-10-23)
- Mechanical Permit — Seattle Department of Construction and Inspections (accessed 2026-10-23)
- 2026 Fee Subtitle (SMC 22.900), Table D-8 Permit Fees for Mechanical Equipment — SDCI (accessed 2026-10-23)
- Seattle Services Portal — City of Seattle (2026-10-23)
- Plumbing and gas piping applications and permits — Public Health – Seattle & King County (2026-10-22)