Hiring an HVAC contractor in Seattle: L&I, the City refrigeration license, permits, and what 34,000 permits show

Seattle HVAC in numbers

Heat-pump permits take longer to close (105 days against 66), partly because the refrigeration, electrical and sometimes furnace permits all need their own final. Which system to choose is a separate question: heat pump vs furnace in Seattle.

Which license a Seattle HVAC contractor needs

Washington requires all construction contractors to register with L&I and carry a bond: $30,000 for a general contractor, $15,000 for a specialty contractor, who "can work only in the specialty they're registered for and cannot hire subcontractors" (L&I, read 22 October 2026). Seattle adds two licenses of its own: the SDCI refrigeration contractor license, which "allows your business to install, repair, or alter refrigeration or air conditioning equipment" and needs a journeyman refrigeration mechanic assigned, and the gas piping license for piping "from the meter to the appliance" (SDCI, read 22 October 2026). Whoever handles refrigerant also needs EPA Section 608 certification.

The five-minute check: search the firm on L&I Verify (status, specialty, bond lawsuits, workers' comp), then on the Seattle Services Portal use "Find Trade Licenses by Last Name" for the refrigeration or gas piping license. The Seattle contractor license lookup has the rest.

The permit rule in Seattle

SDCI's furnace and refrigeration guide says "You need a permit for any furnace replacement or alteration" and "You need a refrigeration permit for any split system heat pump, air conditioner." A homeowner can get a furnace or mechanical permit for their own work, but for a refrigeration permit "Homeowners need to hire a contractor", because only licensed refrigeration contractors can get one. Both need a cover inspection for the heat pump, AC, furnace and ducts, and a final once the install is done (SDCI, read 23 October 2026). Building without a required permit can bring fines of "up to $500 per day" (SDCI).

On money: Seattle City Light's heat-pump discount of $300 to $600, by efficiency, is passed on in the bid only when the contractor buys from a participating distributor (Seattle City Light, read 21 October 2026). Ask, in writing, whether yours does.

Red flags in the Seattle record

• A completion share under the 10th-percentile line: 69.1% for furnaces, 64.8% for heat pumps. Ask about the open permits by address.
• An L&I record that is not active. 40 furnace firms (12.7%) and 36 heat-pump firms on Seattle permits matched an L&I registration that is no longer active. Busy firms are among them, so check every firm you quote, today.
• A heat-pump installer with no Seattle refrigeration license, or one that asks you to get the permit: you cannot, for refrigeration work.
• A firm that stopped filing. 21 furnace firms and 19 heat-pump firms with 5 or more permits filed none in the last 12 months.
• A quote far outside the middle half of filed values in the table above. Compare like with like: a ducted heat pump and a single mini-split head file very differently.

The busiest Seattle firms in the last 12 months

Ranked by permits in the last 12 months of the window. Volume, not quality.

The busiest furnace firm alone filed 14.6% of Seattle's furnace and heating permits. Completion share and L&I status for each firm are on the compare lists.

See every Seattle heat-pump installer by completion and L&I status →

What the Seattle record does not tell you

A completed permit means the inspections passed, not that the system was sized for your house or the refrigerant charge is right. Permits carry no L&I number, so we match firms by business name; we do not match SDCI refrigeration or gas piping licenses. Filed values exclude the separate electrical permit. Insurance never appears on a permit. For the furnace list, see the Seattle furnace and heating compare page; for the national checklist, hiring an HVAC contractor.