Zone 1BVery Hot (Zone 1)
Climate Zone 1B - Very Hot, Dry
Very hot summers with low humidity. Extreme temperature swings between day and night. This climate zone encompasses parts of Arizona, California, Nevada, Texas and includes major cities like Phoenix, Tucson, Las Vegas, Palm Springs.
Design Temperatures
Winter Design Temperatures
25°F to 40°F
Used for heating load calculations and equipment sizing
Summer Design Temperatures
100°F to 115°F
Used for cooling load calculations and equipment sizing
Heating & Cooling Degree Days
Heating Degree Days (HDD)
500 - 2,500
Base 65°F. Higher numbers indicate more heating requirements and longer heating seasons.
Cooling Degree Days (CDD)
4,000 - 6,000
Base 65°F. Higher numbers indicate more cooling requirements and longer cooling seasons.
HVAC System Considerations
Key Considerations
- •Extreme cooling loads
- •UV protection critical
- •Dust filtration important
- •Equipment derating for high temps
- •Large temperature swings
Common Equipment
- ✓High-capacity air conditioners
- ✓Evaporative cooling (swamp coolers)
- ✓Two-stage or variable speed systems
- ✓Heat pumps with auxiliary heat
Energy Code Requirements
Equipment Efficiency
- ⚠SEER 14+ minimum
- ⚠High-performance fenestration
- ⚠Radiant barrier requirements
- ⚠Duct insulation R-8 minimum
Insulation Requirements
Walls:R-13 to R-15
Ceiling:R-38 to R-49
Floor:R-13 (if applicable)
Major Cities in Zone 1B
States with Zone 1B Areas
Quick Reference
Zone:1B
Temperature:Very
Moisture:Dry (B)
States:4
Cities:4
Calculate Load
Use our load calculators with the design temperatures and requirements specific to Zone 1B.