Frederick Climate Zone & Energy Code

Climate Zone: IECC Climate Zone 4A (mixed-humid). Frederick's western Maryland position is slightly cooler than Baltimore and DC due to Catoctin Mountain influence, but shares the same mixed-humid climate classification with both summer and winter HVAC demands.

Energy Code & Manual J Requirement: Maryland Building Performance Standards (IECC 2021). ACCA Manual J required for Frederick County HVAC permits.

Local Electric Utility: Potomac Edison (FirstEnergy)

Building Department: City of Frederick Department of Planning & Building

Local Trade Association: ACCA Mid-Atlantic Chapter