What's Required in San Francisco
- A mechanical permit is required to install or replace a furnace, heat pump, ductless split or ductwork; Category 1M covers one residential unit for $290.
- Plumbing and mechanical work need separate permits, so a new or relocated gas line to the equipment is a second permit.
- A new circuit, disconnect or subpanel for the equipment needs an electrical permit ($305 for up to 10 devices).
- Only appliance repair or replacement with no change to existing wiring is exempt from the electrical permit.
- A contractor must hold a C-20, C-36/C-4, B or other qualifying license and be registered with the City to apply.
- Homeowner mechanical permits are limited to owner-occupied stand-alone single-family houses where the owner does the work.
- Pipes and ducts must be inspected before they are covered; Category 1M includes a maximum of two inspections.
- New mechanical equipment that requires a building permit needs plans and an over-the-counter building permit in addition to the trade permits.
Do You Need a Permit to Replace a Furnace or Install a Heat Pump in San Francisco?
Yes. The Department of Building Inspection (DBI) requires a plumbing or mechanical permit before you cut into or replace pipes that transport water, gas, hot air or cool air, and its mechanical permit worksheet lists the residential case by name: Category 1M, a mechanical gas appliance such as a furnace, hydronic heat or heat pump in a single residential unit. A like-for-like furnace swap, a new heat pump or ductless split, ductwork changes and a new gas line to the equipment are all permitted work. The electrical side is separate: a new circuit or disconnect for a heat pump or condenser needs an electrical permit, though the Electrical Code exempts repair or replacement of a domestic appliance where no change in existing wiring is involved. If the equipment needs a building permit, for example a rooftop or exterior unit that DBI treats as new mechanical equipment, plans are required for that building permit.
San Francisco HVAC Permit Rules by Scenario
| What you are doing | City filing | Rule |
|---|---|---|
| Thermostat, filter, blower motor or control board repair on existing wiring | No electrical permit | SF Electrical Code 89.121(B) and (C) exemptions; mechanical permit only if piping is cut |
| Like-for-like gas furnace replacement in one home | Mechanical permit, Category 1M | $290, maximum two inspections |
| Heat pump or ductless split replacing a furnace | Mechanical permit + electrical permit | $290 plus $305 for up to 10 devices |
| New gas line or relocated gas piping to the equipment | Plumbing permit | Separate permit from the mechanical permit |
| Furnaces or heat pumps in a 2-to-6-unit building | Mechanical permit, Category 2M | $420, maximum three inspections |
| New rooftop or exterior equipment that needs a building permit | Building permit with plans + trade permits | DBI requires plans for new mechanical equipment inside or outside |
| Work not covered by a category | Mechanical permit at hourly rate | $519 per hour |
How Much Does an HVAC Permit Cost in San Francisco?
DBI's plumbing and mechanical fees are flat categories in Table 1A-C, in force for permits issued on or after July 12, 2026. A furnace, hydronic system or heat pump in a single residential unit is Category 1M, $290, with up to two inspections included; a building of six or fewer units doing the same work is Category 2M at $420, and anything the categories do not cover is billed at $519 per hour. Plumbing and mechanical need separate permits, so a new gas run to a furnace adds a plumbing permit, and a heat pump that needs a new circuit or disconnect adds an electrical permit from Table 1A-E: $305 for up to 10 outlets or devices, where the appliance itself counts as one, or $450 for 11 to 20. That puts a straight furnace swap at $290 and a heat pump conversion with its electrical permit at about $595, roughly $710 if the wiring runs past 10 devices. There is no valuation formula on a mechanical permit; the worksheet asks for the cost of the job but the fee is the category. Re-inspections are $259 per half hour, and every permit is per structure or unit.
Who Can Pull an HVAC Permit in San Francisco?
A contractor registered with the City holding a C-20 warm-air heating license for the mechanical permit, a C-36 or C-4 for the plumbing permit, or a B general contractor after DBI approves the scope; DBI's list also admits A, C16 and C54 licenses within their own scopes. Contractors authorized for Express Permits on PermitSF skip staff review and pay immediately. Homeowners may take out a mechanical permit only for a stand-alone single-family house they own and only for work they do themselves; homeowner mechanical permits are approved at Inspection Services on the fourth floor, and after filing online you have a week to see an inspector at the Permit Center help desk, who can require you to hire a contractor instead. Owners of condos and flats must use a licensed contractor.
How the Process Works
The PermitSF form asks for the building type and number of stories, the type of mechanical work, the number of units, the estimated value of labor and materials and the contractor's details; if the job also needs plumbing, you file a second permit for that scope. Once issued, the work must be inspected before pipes or ducts are covered, and the two inspections in Category 1M are typically rough and final. Where a building permit is triggered, that application goes over the counter with two sets of plans and Planning review of any exterior equipment. Fees are due before the final sign-off, and a new boiler must be registered separately after the plumbing permit is approved.
How to Get a HVAC Permit in San Francisco
Sort the scopes
Furnace, heat pump or ducts is a mechanical permit; gas piping is a plumbing permit; a new circuit is an electrical permit. Each is filed separately.
Apply on PermitSF
A registered C-20 or approved B contractor enters the building type, work type, unit count and job value; Express Permit contractors skip review. Homeowners of stand-alone houses file, then see an inspector within a week.
Pay the flat fees
$290 for Category 1M (one home) or $420 for Category 2M (two to six units), plus $305 and up for the electrical permit; permits issue once paid.
Install and call for rough inspection
Have gas piping, ducts and wiring inspected before they are covered; the mechanical permit includes two inspections.
Final sign-off
Request the final from PermitSF; fees must be paid in full before sign-off, and any boiler is registered separately afterward.