Replacing a furnace, heat pump, central air conditioner or ductless mini-split almost always involves more than one sign-off. Between Seattle and Everett a typical swap touches two separate permit systems, electrical and mechanical, and Seattle adds a refrigeration permit for split systems. Which office issues each one depends on the address, not on the equipment brand or the installer. This is how it sorts out under the state rules and the city pages we checked.
Fixing a part is not the same as replacing the unit
Washington's rule (WAC 296-46B-901) starts from the position that electrical installation, alteration and maintenance all need a permit, then carves out a short list of minor work. On that list are like-in-kind swaps of contactors, relays, timers and control boards, one motor of 10 horsepower or smaller, and up to five thermostats or heating elements. That is why a new contactor on an outdoor unit or a replacement blower motor in a furnace normally goes ahead without a permit.
The same rule closes the obvious loophole: replacing an entire equipment unit that contains those exempt components is not exempt, and the WAC names an electric furnace or heat pump as its example. A new furnace, air handler, outdoor unit or mini-split head is permit work even when it lands on the same circuit in the same spot.
Who issues the electrical permit at your address
For much of our area the answer is L&I. Five cities we serve issue electrical permits themselves and send their own inspectors inside city limits: Seattle, Everett, Kirkland, Lynnwood and Mountlake Terrace. In Bothell, Edmonds, Shoreline, Mill Creek, Mukilteo, Kenmore, Woodinville, Lake Forest Park and Brier, the electrical permit comes from the state. L&I keeps the current list on its city electrical permits page.
Straight swaps and the Class B label
Where L&I inspects, a straight swap can go on a Class B label rather than a full permit (WAC 296-46B-908). Two items on that list matter here: a like-in-kind furnace on a supply of 240 volts or less and 100 amps or less, and a like-in-kind heat pump, air conditioner or refrigeration unit at 240 volts or less with a minimum circuit ampacity no higher than 40. In both cases the new unit must connect to the existing branch circuit, and the label also takes in the associated low-voltage control wiring. Labels are sold only to electrical contractors, must be posted before the work starts, and are inspected on a random basis rather than every time. Cities with their own inspection programs do not accept them.
Like-in-kind has a defined meaning: the same overcurrent protection, similar voltage, current draw and short-circuit characteristics, and the same function and location. If the new heat pump calls for a bigger breaker, or the unit moves to another wall, the swap no longer qualifies and goes on a regular permit with an inspection. Any new circuit or changed breaker is also outside the HVAC/refrigeration specialty; it belongs to a general (01) or residential (02) electrical contractor.
The mechanical permit comes from the city
Setting the equipment, venting, duct connections and refrigerant lines fall under separate permits from the city building department. Seattle's SDCI states that any furnace replacement or alteration needs a permit, and that a heat pump or AC built as a split system, or any job with refrigeration piping, also needs a refrigeration permit. That refrigeration permit can only be obtained with a contractor who holds a City of Seattle refrigeration license; a Seattle homeowner may take out the furnace permit but not that one. Shoreline lists replacing a furnace or heat pump and installing a new heat pump or mini-split among its residential mechanical permits. The other cities set their own requirements and fees, so their permit desks are the place to confirm. If a gas line has to be moved or extended, L&I notes that gas and plumbing connections may need a building or plumbing permit from the city or county as well.
Who buys the permit
The business doing the work buys its own permit. L&I's permit basics page is direct about it: a permit bought by someone else cannot be used, and its example is a hired worker asking the homeowner to buy one. Two businesses cannot share a permit either. Only a property owner doing the work personally, or an electrical contractor, can purchase an electrical permit at all. So the request to put the permit in your name is not a shortcut; it leaves the installer's work unpermitted, and L&I lists it among the warning signs when hiring. On the installs we take on, the permit paperwork is ours to handle, not yours.
How the inspections run
On the electrical side, the inspection request is due within three working days of finishing, or within one working day of the first time any of it is energized, whichever deadline arrives sooner, and before anything is covered up. Seattle's mechanical process adds cover inspections for heat pumps, air conditioners, furnaces and duct systems after rough-in and before anything is closed in, then a final once the installation is complete. Seattle also has a noise limit worth knowing before you pick a spot: a heat pump may produce no more than 45 decibels at the property line, and equipment placed in a side yard goes through a noise review.
Why a closed permit matters to you
L&I warns that missing permits could affect your ability to sell, finance or insure the property. A permit with a passed final is the record that answers that question years later, when a buyer, a lender or an insurer asks how the heat pump went in. You can check it yourself. L&I's permit lookup searches by site address or permit number for permits bought since January 1, 2020; for Seattle and the other city-inspected addresses, use the city's own portal. If a new system went in and nothing turns up, ask the installer for the permit number before the final payment.
Planning a replacement
If your system is near the end, our AC and heat pump page covers repair and installation, and furnace repair and replacement covers gas and electric furnaces. The electrical specialty we install under is described on our HVAC/refrigeration 06A page, and the full set of credentials is on licenses. Call (425) 570-9520 or book online to set up an install site visit.