Do you need a permit for an AC unit, heat pump, or generator in San Francisco, CA?
It depends on the details of your project.
San Francisco's mechanical permit worksheet lists heat pumps and furnaces.
Mechanical permits need a contractor with a C20 license, or the owner of a stand-alone single-family home.
Gas piping to a generator or furnace needs a plumbing permit.
A person last checked these rules on October 22, 2026. This is guidance only, so confirm with San Francisco before you build.
Check your exact lot
Your zoning district sets the setbacks, and a flood zone can change the permit answer. Enter your address to see both.
Permits a AC unit, heat pump, or generator can need in San Francisco
| Permit | When it applies |
|---|---|
| Mechanical permit | San Francisco requires a mechanical permit to install or replace heat pumps and furnaces and the pipes that carry hot or cool air.Medium confidence |
| Electrical permit | A standby generator needs an electrical permit for its transfer switch. A new outdoor unit needs a new circuit and disconnect.Medium confidence |
| Plumbing permit (gas piping) | San Francisco requires a plumbing permit to cut into or replace gas piping. |
Local details
- Call 811 at least a few days before you dig footings or post holes. Utility locating is free.
- HOA covenants and deed restrictions can be stricter than city rules. Check yours before you build.
How to apply
- Check if your project needs a permit (sf.gov)
- SF Property Information Map
- Phone: (628) 652-3200
Common questions
- When does an AC unit, heat pump, or generator need a mechanical permit in San Francisco?
- San Francisco requires a mechanical permit to install or replace heat pumps and furnaces and the pipes that carry hot or cool air. Generators are covered by the electrical permit.
- Where do I apply for an AC unit, heat pump, or generator permit in San Francisco?
- Apply through Check if your project needs a permit (sf.gov), or call (628) 652-3200.
Sources
- sf.gov, Apply for a plumbing and mechanical permit. Checked 2026-10-22
[You need a permit before] cutting into or replacing pipes that transport water, gas, hot air, or cool air... Contractors must hold a C4, C16, C20, C36, C54, B, or A license to apply for a plumbing or mechanical permit in general.
- SF DBI, Mechanical permit application worksheet. Checked 2026-10-22
Mechanical gas appliance - furnace, hydronic heat, heat pump
- sf.gov, Apply for an electrical permit. Checked 2026-10-22
You need an electrical permit before installing new wiring or alterations, extensions, or additions [to existing electrical installations]... Only owner-installers of stand-alone single family dwellings may apply for an electrical permit to do the work them…