Climate Zone 2A - Hot, Humid
Hot summers with high humidity. Mild winters requiring some heating. This climate zone encompasses parts of Louisiana, Mississippi, Alabama, Georgia, Texas, Florida and includes major cities like Houston, New Orleans, Mobile, Savannah.
Common Questions About Zone 2A
Zone 2A definition
This page explains what IECC climate zone 2A means in HVAC and building-code terms.
Cities in zone 2A
Use the city examples below to answer common lookup searches for this zone.
Heating and cooling profile
See whether zone 2A 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 2A Means
Temperature class
Hot (Zone 2)
Moisture class
Moist (A)
Load priority
Cooling-dominant
Quick definition
Hot summers with high humidity. Mild winters requiring some heating.
Common City Lookups for Zone 2A
| City | IECC zone answer | Why it matters |
|---|---|---|
| Houston | Houston is commonly treated as IECC climate zone 2A in this guide. | High cooling loads with humidity control |
| New Orleans | New Orleans is commonly treated as IECC climate zone 2A in this guide. | High cooling loads with humidity control |
| Mobile | Mobile is commonly treated as IECC climate zone 2A in this guide. | High cooling loads with humidity control |
| Savannah | Savannah is commonly treated as IECC climate zone 2A in this guide. | High cooling loads with humidity control |
| Jacksonville | Jacksonville is commonly treated as IECC climate zone 2A in this guide. | High cooling loads with humidity control |
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
- •High cooling loads with humidity control
- •Moderate heating requirements
- •Mold and moisture management
- •Hurricane considerations in coastal areas
- •Year-round humidity concerns
Common Equipment
- ✓Heat pumps with backup heat
- ✓High-efficiency AC with dehumidification
- ✓Dual-fuel systems
- ✓Whole-house dehumidifiers
Energy Code Requirements
Equipment Efficiency
- ⚠SEER 13+ minimum
- ⚠HSPF 7.7+ for heat pumps
- ⚠Moisture control strategies
- ⚠Duct leakage testing
Insulation Requirements
Major Cities in Zone 2A
Quick Reference
Calculate Load
Use our load calculators with the design temperatures and requirements specific to Zone 2A.