Kern County is in IECC Climate Zone 3B (Warm - Dry). Get accurate Manual J load calculations with official ASHRAE design temperatures for Kern County.
Kern County, California is classified under IECC Climate Zone 3B (Warm - Dry), a mixed-climate region with dry moisture conditions. With 69 ZIP codes and 1 communities, every HVAC installation in Kern County must use the ASHRAE design temperatures of 21°F (99% winter heating) and 108°F (1% summer cooling) for accurate Manual J load calculations.
With balanced heating and cooling loads, Kern County homes require well-rounded insulation — R-20 walls, R-30 ceilings, R-19 floors — and windows with both U-factor 0.32 and SHGC 0.25 to handle both winter lows and summer highs.
Minimum insulation R-values and window performance for Climate Zone 3B in Kern County, CA.
| Building Component | Minimum Requirement | Unit |
|---|---|---|
| Ceiling / Attic Insulation | R-30 | R-value |
| Wall Insulation | R-20 | R-value |
| Floor Insulation | R-19 | R-value |
| Window U-Factor | 0.32 | BTU/hr-ft²-°F |
| Window SHGC | 0.25 | Coefficient |
| Air Infiltration | 0.15 | ACH50 |
Climate Zone 3B requires precise load calculations. Upload your Kern County blueprint and get a professional Manual J report in 60 seconds— first report is FREE. Pre-loaded with Kern County's exact design temperatures (21°F winter / 108°F summer).
Enter your ZIP code to confirm it's in Kern County and get climate zone details.
Official ASHRAE design temperatures for Kern County, CA, used for accurate Manual J load calculations.
Minimum insulation and window requirements for Kern County per IECC 2021 energy code.
Climate Zone 3B: Warm - Dry - Warm climate with low humidity, hot summers and cool winters. Moderate heating and cooling loads.
1 cities and communities in Kern County share Climate Zone 3B requirements.
Compare climate zones with other counties in California. Different zones require different HVAC equipment sizing.
Upload your Kern County blueprint and get a professional Manual J load calculation using official Zone 3B design temperatures. First report is FREE.
Join 10,000+ California contractors who trust AutoHVAC