Permits by Project
Do You Need a Permit for HVAC equipment replacement?
Of the 10 areas we checked, a permit is required in 4, it depends on the scope in 5 and we found no official answer in 1.
Washington, DC
Washington, DC
Permit required- When it applies
- 'New and replacement HVAC equipment' require a permit
- Permits
- Mechanical
- Faster route
- Instant Mechanical Permit
Source: DOB How to Get a Permit; DOB Instant Permits, checked 2026-10-07
Maryland
Anne Arundel County, MD
Not confirmed- Notes
- No official answer found. mechanical trade permits exist via I&P Licensing, but the HVAC replacement threshold is not published on pages reviewed.
Ask the permit office: Department of Inspections and Permits
Charles County, MD
Depends- When it applies
- Gas/oil-fired equipment: yes (mechanical + plumbing/gas trade permits). Electric like-for-like: threshold not published.
- Permits
- Mechanical, Plumbing, Gas
- Notes
- Mechanical and Plumbing & Gas trade permits/inspections exist per PGM fee schedule.
Source: PGM FY2027 Fees & Charges, checked 2026-10-07
Montgomery County, MD
Permit required- When it applies
- mechanical permit required to 'install, enlarge, alter, repair, remove, convert or replace' HVAC
- Permits
- Mechanical, Electrical, Gas
- Who pulls it
- A licensed contractor
- Faster route
- Online residential mechanical permits
- Notes
- Exempt: portable units, minor parts, self-contained refrigeration ≤12,000 BTU, basement finishing limited to ductwork/exhaust fans. Gas work via WSSC.
Source: DPS Residential Mechanical permit process, checked 2026-10-07
Prince George's County, MD
Permit required- When it applies
- all HVAC installs: electric AC/heat pump/furnace = E, M*; gas furnace/boiler = E, M, P*
- Permits
- Electrical, Mechanical, Plumbing, Gas
- Who pulls it
- A licensed contractor
- Notes
- 'Install gas furnace E, M, P* N'; 'Install heat pump E, M* N'. Cord-and-plug window A/C = no permit ('Install portable cooling unit N N').
Source: DPIE Homeowner's Guide to Permits, checked 2026-10-07
Northern Virginia
Arlington County, VA
Depends- When it applies
- Same type/size/location NON-GAS replacement = no mechanical permit; GAS-FUELED equipment replacement = Plumbing/Gas Permit required
- Permits
- Mechanical, Plumbing, Gas
- Notes
- Exact per county mechanical page; USBC 108.2 exemptions also apply.
Source: Arlington Mechanical Permit page, checked 2026-10-07
City of Alexandria, VA
Depends- When it applies
- USBC 108.2(14.4): replacement of mechanical appliances NOT fueled by gas or oil = exempt; gas/oil-fueled = permit
- Permits
- Mechanical, Gas
- Notes
- No Alexandria-specific threshold found; statewide code applies.
Source: USBC 13VAC5-63-80 Section 108.2, checked 2026-10-07
Fairfax County, VA
Permit required- When it applies
- LDS: 'New, Replacement, Repair or Conversion of HVAC Systems' requires a mechanical permit
- Permits
- Mechanical
Source: LDS Permit Library: Residential Building, checked 2026-10-07
Loudoun County, VA
Depends- When it applies
- USBC 108.2(14.4): gas/oil-fueled = permit; otherwise exempt
- Permits
- Mechanical, Gas
- Faster route
- LandMARC online
- Notes
- County issues mechanical and gas trade permits.
Source: USBC 13VAC5-63-80 Section 108.2, checked 2026-10-07
Prince William County, VA
Depends- When it applies
- Replacing GAS OR OIL furnaces = permit always required; electric same-for-same replacement threshold not published
- Permits
- Mechanical, Gas
- Faster route
- ePortal online
- Notes
- 'alterations to... heating and air conditioning (mechanical) systems' always require a permit.
Source: PWC Do I Need a Permit?, checked 2026-10-07
Summarized from each area’s official permit pages and codes, as of October 2026. Some Maryland municipalities issue their own permits, rules change, and many answers depend on the exact scope, so confirm with the permit office before work starts. This is general information, not legal advice.
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