Rockville Climate Zone & Energy Code

Climate Zone: IECC Climate Zone 4A (mixed-humid). Rockville's DC suburb location produces hot, humid summers (91°F/73°F cooling design) and cold winters (13°F heating design) typical of the Mid-Atlantic mixed-humid classification.

Energy Code & Manual J Requirement: Maryland Building Performance Standards (IECC 2021). ACCA Manual J required for residential HVAC permits. Montgomery County has its own building permits division enforcing state energy code.

Local Electric Utility: Pepco (Potomac Electric Power / Exelon)

Building Department: City of Rockville Building & Code Enforcement

Local Trade Association: ACCA Mid-Atlantic Chapter / ASHRAE Chesapeake Chapter