Zone 3CWarm (Zone 3)
Climate Zone 3C - Warm, Marine
Mild temperatures year-round with marine influence. Limited heating and cooling needs. This climate zone encompasses parts of California, Oregon and includes major cities like San Francisco, Los Angeles, San Diego, Eureka.
Design Temperatures
Winter Design Temperatures
25°F to 40°F
Used for heating load calculations and equipment sizing
Summer Design Temperatures
75°F to 85°F
Used for cooling load calculations and equipment sizing
Heating & Cooling Degree Days
Heating Degree Days (HDD)
1,500 - 3,000
Base 65°F. Higher numbers indicate more heating requirements and longer heating seasons.
Cooling Degree Days (CDD)
0 - 1,000
Base 65°F. Higher numbers indicate more cooling requirements and longer cooling seasons.
HVAC System Considerations
Key Considerations
- •Minimal cooling needs
- •Moderate heating requirements
- •High humidity from marine air
- •Corrosion from salt air
- •Mild temperature swings
Common Equipment
- ✓Heat pumps
- ✓Ductless mini-splits
- ✓Radiant heating
- ✓High-efficiency gas furnaces
Energy Code Requirements
Equipment Efficiency
- ⚠SEER 13+ minimum
- ⚠HSPF 7.7+ for heat pumps
- ⚠AFUE 80+ for furnaces
- ⚠Enhanced building envelope
Insulation Requirements
Walls:R-13 to R-15
Ceiling:R-30 to R-38
Floor:R-19 to R-25
Major Cities in Zone 3C
States with Zone 3C Areas
Quick Reference
Zone:3C
Temperature:Warm
Moisture:Marine (C)
States:2
Cities:4
Calculate Load
Use our load calculators with the design temperatures and requirements specific to Zone 3C.