Do you need a permit for an AC unit, heat pump, or generator in Arlington County, VA?
It depends on the details of your project.
AC units, heat pumps and generators must be at least 8 ft from a side line and 10 ft from the rear line.
Screened equipment may sit closer, in any required yard.
Outdoor equipment doesn't count toward lot coverage.
A person last checked these rules on October 20, 2026. This is guidance only, so confirm with Arlington County 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 Arlington County
| Permit | When it applies |
|---|---|
| Mechanical permit | New heating and cooling systems, and any gas- or oil-fired equipment, need a mechanical permit. |
| Electrical permit | A standby generator and its transfer switch, or a new outdoor unit's circuit, need an electrical permit.Medium confidence |
| Gas piping permit | A gas or propane line needs a fuel-gas permit.Medium confidence |
| Certificate of Appropriateness (HALRB) | In a local historic district, exterior changes need a Certificate of Appropriateness from the Historical Affairs and Landmark Review Board. |
Limits that apply citywide
| Unscreened equipment | At least 8 ft from any side lot line and 10 ft from any rear lot line |
|---|---|
| Screened equipment | May encroach into a required front, side or rear yard when screened by a fence or vegetation |
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 Arlington County?
- New heating and cooling systems, and any gas- or oil-fired equipment, need a mechanical permit. Replacing an electric mechanical appliance in a house is exempt from permit in Virginia (USBC 108.2 item 14.4).
- Where do I apply for an AC unit, heat pump, or generator permit in Arlington County?
- Apply through Arlington Permits portal, or call 703-228-3800.
Sources
- Virginia USBC, 13VAC5-63-80 Section 108.2, Exemptions from application for permit. Checked 2026-10-23
2. One story detached structures used as tool and storage sheds, playhouses, or similar uses, provided the building area does not exceed 256 square feet... 5. Fences of any height unless required for pedestrian safety as provided for by Section 3306 or used…
- Arlington County, Certificate of Appropriateness. Checked 2026-10-23
A certificate of appropriateness (CoA) is required for all proposed exterior alterations, new construction and demolition within a local historic district, with the exception of routine maintenance, repairs and replacements using the same materials, interio…
- Arlington County Zoning Ordinance §§ 3.2.5, 3.2.6.A.4, 12.9.9, 12.9.11, 12.9.12, 12.9.16, 12.9.17 and Article 18. Checked 2026-10-21
[Visual clearance] On any corner lot in an R or RA district there shall be no planting, structure, retaining wall, fence, shrubbery or obstruction to vision between a height of three feet and a height of 10 feet above the curb level within the triangle form…