Zone 3AWarm (Zone 3)
Climate Zone 3A - Warm, Humid
Warm summers with humidity. Moderate heating and cooling needs throughout the year. This climate zone encompasses parts of North Carolina, South Carolina, Georgia, Alabama, Tennessee, Arkansas, Virginia and includes major cities like Atlanta, Charlotte, Memphis, Birmingham.
Design Temperatures
Winter Design Temperatures
10°F to 25°F
Used for heating load calculations and equipment sizing
Summer Design Temperatures
85°F to 95°F
Used for cooling load calculations and equipment sizing
Heating & Cooling Degree Days
Heating Degree Days (HDD)
2,500 - 4,000
Base 65°F. Higher numbers indicate more heating requirements and longer heating seasons.
Cooling Degree Days (CDD)
1,500 - 3,000
Base 65°F. Higher numbers indicate more cooling requirements and longer cooling seasons.
HVAC System Considerations
Key Considerations
- •Balanced heating and cooling loads
- •Humidity control important
- •Moderate equipment sizing
- •Seasonal changeover systems
- •Mold prevention
Common Equipment
- ✓Heat pumps
- ✓Gas furnaces with AC
- ✓Dual-fuel systems
- ✓Variable speed equipment
Energy Code Requirements
Equipment Efficiency
- ⚠SEER 13+ minimum
- ⚠HSPF 7.7+ for heat pumps
- ⚠AFUE 80+ for furnaces
- ⚠Duct insulation R-6 minimum
Insulation Requirements
Walls:R-13 to R-15
Ceiling:R-30 to R-38
Floor:R-19 to R-25
Major Cities in Zone 3A
States with Zone 3A Areas
Quick Reference
Zone:3A
Temperature:Warm
Moisture:Moist (A)
States:7
Cities:5
Calculate Load
Use our load calculators with the design temperatures and requirements specific to Zone 3A.