Billings Climate Zone & Energy Code
Climate Zone: IECC Climate Zone 6B (cold-dry). Billings's 3,100-foot elevation produces hot, dry summers (94°F/62°F cooling design, very low latent loads) and very cold winters (-9°F heating design). Altitude derating of equipment capacity (~90% of sea level) is required in Manual S.
Energy Code & Manual J Requirement: Montana Residential Building Code (IECC 2021). ACCA Manual J required for Yellowstone County HVAC permits.
Local Electric Utility: NorthWestern Energy
Building Department: City of Billings Building Inspection Division
Local Trade Association: PHCC Montana / ASHRAE Montana Chapter