Climate Zone 6A - Cold, Humid
Short warm summers and long cold winters. Very high heating loads. This climate zone encompasses parts of Minnesota, Wisconsin, Michigan, Maine, Vermont, New Hampshire, New York and includes major cities like Minneapolis, Milwaukee, Detroit, Burlington.
Common Questions About Zone 6A
Zone 6A definition
This page explains what IECC climate zone 6A means in HVAC and building-code terms.
Cities in zone 6A
Use the city examples below to answer common lookup searches for this zone.
Heating and cooling profile
See whether zone 6A is heating-dominant, cooling-dominant, or balanced.
HVAC requirements
Compare design temperatures, degree days, code requirements, and equipment guidance for this zone.
What IECC Climate Zone 6A Means
Temperature class
Cold (Zone 6)
Moisture class
Moist (A)
Load priority
Heating-dominant
Quick definition
Short warm summers and long cold winters. Very high heating loads.
Common City Lookups for Zone 6A
| City | IECC zone answer | Why it matters |
|---|---|---|
| Minneapolis | Minneapolis is commonly treated as IECC climate zone 6A in this guide. | Extremely high heating loads |
| Milwaukee | Milwaukee is commonly treated as IECC climate zone 6A in this guide. | Extremely high heating loads |
| Detroit | Detroit is commonly treated as IECC climate zone 6A in this guide. | Extremely high heating loads |
| Burlington | Burlington is commonly treated as IECC climate zone 6A in this guide. | Extremely high heating loads |
| Syracuse | Syracuse is commonly treated as IECC climate zone 6A in this guide. | Extremely high heating loads |
Design Temperatures
Winter Design Temperatures
Used for heating load calculations and equipment sizing
Summer Design Temperatures
Used for cooling load calculations and equipment sizing
Heating & Cooling Degree Days
Heating Degree Days (HDD)
Base 65°F. Higher numbers indicate more heating requirements and longer heating seasons.
Cooling Degree Days (CDD)
Base 65°F. Higher numbers indicate more cooling requirements and longer cooling seasons.
HVAC System Considerations
Key Considerations
- •Extremely high heating loads
- •Short cooling season
- •Freeze protection essential
- •Snow and ice loads
- •Equipment cold weather performance
Common Equipment
- ✓High-efficiency gas furnaces
- ✓Boilers
- ✓Cold climate heat pumps
- ✓Radiant heating systems
Energy Code Requirements
Equipment Efficiency
- ⚠SEER 13+ minimum
- ⚠HSPF 8.2+ for heat pumps
- ⚠AFUE 90+ for furnaces
- ⚠Continuous insulation required
Insulation Requirements
Major Cities in Zone 6A
Quick Reference
Calculate Load
Use our load calculators with the design temperatures and requirements specific to Zone 6A.