AC units, heat pumps and generators in Montgomery County, MD
AC units, heat pumps and generators may project up to 5 ft into a front or rear setback. Even replacing heating equipment needs a permit. Noise at the property line: 65 dBA by day, 55 dBA at night.
A person last checked these rules on October 20, 2026. This is guidance only, so confirm with Montgomery County before you build.
The details
- Day is 7 a.m. to 9 p.m. on weekdays and 9 a.m. to 9 p.m. on weekends and holidays.High confidence
Check a project at your address
SetbackIQ reads the zoning, flood zone, historic district, and environmental maps for your lot. Then it applies these rules.
Common questions
- Where can outdoor mechanical equipment go in Montgomery County?
- AC units, heat pumps and generators may project up to 5 ft into a front or rear setback. Even replacing heating equipment needs a permit. Noise at the property line: 65 dBA by day, 55 dBA at night.
Sources
- Montgomery County DEP, Noise brochure (Chapter 31B). Checked 2026-10-21
Daytime: 65 decibels (Weekdays: 7 am to 9 pm; Weekends and holidays: 9 am to 9 pm). Nighttime: 55 decibels... Construction noise may not exceed 75 decibels [unless a Noise Suppression Plan allows more].
Disclaimer: This is general information, not legal or professional advice for any one property. Codes change. SetbackIQ is not a zoning determination, a permit, or a survey, and it does not replace an architect, engineer, or lawyer. Confirm with your building and zoning offices before you build, buy, or sign a contract.