Zone 7Very Cold (Zone 7)
Climate Zone 7 - Very Cold
Short cool summers and very long cold winters. Heating loads dominate completely. This climate zone encompasses parts of Alaska, Minnesota, North Dakota, Montana and includes major cities like Duluth, International Falls, Fargo, Great Falls.
Design Temperatures
Winter Design Temperatures
-30°F to -10°F
Used for heating load calculations and equipment sizing
Summer Design Temperatures
65°F to 75°F
Used for cooling load calculations and equipment sizing
Heating & Cooling Degree Days
Heating Degree Days (HDD)
8,000 - 12,000
Base 65°F. Higher numbers indicate more heating requirements and longer heating seasons.
Cooling Degree Days (CDD)
0 - 250
Base 65°F. Higher numbers indicate more cooling requirements and longer cooling seasons.
HVAC System Considerations
Key Considerations
- •Extreme heating loads
- •No cooling typically needed
- •Equipment cold weather rating critical
- •Freeze protection essential
- •Backup heating systems recommended
Common Equipment
- ✓High-efficiency gas furnaces
- ✓Boilers with backup
- ✓Electric resistance backup
- ✓Radiant heating systems
Energy Code Requirements
Equipment Efficiency
- ⚠AFUE 90+ for furnaces
- ⚠High-performance building envelope
- ⚠Continuous insulation required
- ⚠Advanced air sealing
Insulation Requirements
Walls:R-21+
Ceiling:R-49 to R-60
Floor:R-30+
Major Cities in Zone 7
States with Zone 7 Areas
Quick Reference
Zone:7
Temperature:Very
Moisture:Variable
States:4
Cities:4
Calculate Load
Use our load calculators with the design temperatures and requirements specific to Zone 7.