What San Francisco requires
Do I need a permit to replace a furnace in San Francisco?
Yes, it is mechanical work. The city lets a contractor with one of its listed licenses apply, C20 among them, or the owner of a stand-alone single-family home do it themselves.
- To apply for a mechanical permit in San Francisco, a contractor must hold a C4, C16, C20, C36, C54, B or A license.
- Only owners of stand-alone single-family homes, R-3 occupancy, may apply to do mechanical work themselves.
- A permit to cut into or replace pipes carrying hot or cool air, without plans, can be applied for online.
- The city's Permit Center help desk takes voicemail; leave your email address.
Checked November 2026San Francisco Department of Building Inspection
Checked on sf.gov, November 2026.
