Do you need a permit for an AC unit, heat pump, or generator in Washington, DC?
It depends on the details of your project.
DC requires a permit even to replace HVAC equipment like-for-like.
A gas generator needs electrical and gas permits.
A gas line to the equipment needs a fuel gas permit.
A person last checked these rules on October 20, 2026. This is guidance only, so confirm with Washington 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 Washington
| Permit | When it applies |
|---|---|
| Mechanical permit | DOB lists new and replacement HVAC equipment as work that needs a permit. |
| Electrical permit | A generator's transfer switch, or a new unit's circuit, needs an electrical permit.Medium confidence |
| Gas piping permit | A gas line to the equipment needs a plumbing (fuel gas) permit.Medium confidence |
| Historic Preservation Office review | On a landmark or in a historic district every permit exemption falls away, and HPO reviews exterior work visible from a street before DOB issues the permit. |
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
Common questions
- When does an AC unit, heat pump, or generator need a mechanical permit in Washington?
- DOB lists new and replacement HVAC equipment as work that needs a permit. Generators are permitted under electrical.
- Where do I apply for an AC unit, heat pump, or generator permit in Washington?
- Apply through Department of Buildings, or call (202) 671-3500.
Sources
- DC Department of Buildings, How to get a permit. Checked 2026-10-20
Unless you are in a historic district, the following work does not require a building permit: ... Replacement in-kind of ... Private sidewalks and driveways; Patios ... Single garden storage shed that does not exceed 50 square feet (4.65 m2) in area and is …
- DC Office of Planning, Historic Preservation Office, permit review. Checked 2026-10-21
[The Historic Preservation Review Board, staffed by HPO,] reviews construction affecting those properties [landmarks and properties in historic districts].