Zone 4AMixed (Zone 4)
Climate Zone 4A - Mixed, Humid
Hot summers and cold winters with high humidity. Significant heating and cooling loads. This climate zone encompasses parts of Virginia, Kentucky, Missouri, Kansas, Maryland, Delaware, New Jersey and includes major cities like Richmond, Louisville, Kansas City, St. Louis.
Design Temperatures
Winter Design Temperatures
0°F to 20°F
Used for heating load calculations and equipment sizing
Summer Design Temperatures
80°F to 90°F
Used for cooling load calculations and equipment sizing
Heating & Cooling Degree Days
Heating Degree Days (HDD)
3,000 - 5,500
Base 65°F. Higher numbers indicate more heating requirements and longer heating seasons.
Cooling Degree Days (CDD)
1,000 - 2,000
Base 65°F. Higher numbers indicate more cooling requirements and longer cooling seasons.
HVAC System Considerations
Key Considerations
- •High heating and cooling loads
- •Humidity control year-round
- •Seasonal system changeover
- •Freeze protection
- •Mold and moisture management
Common Equipment
- ✓Heat pumps with backup heat
- ✓Gas furnaces with AC
- ✓Dual-fuel systems
- ✓Central dehumidification
Energy Code Requirements
Equipment Efficiency
- ⚠SEER 13+ minimum
- ⚠HSPF 7.7+ for heat pumps
- ⚠AFUE 80+ for furnaces
- ⚠Duct testing requirements
Insulation Requirements
Walls:R-13 to R-19
Ceiling:R-38 to R-49
Floor:R-19 to R-25
Major Cities in Zone 4A
Quick Reference
Zone:4A
Temperature:Mixed
Moisture:Moist (A)
States:7
Cities:5
Calculate Load
Use our load calculators with the design temperatures and requirements specific to Zone 4A.