St. Helena County is in IECC Climate Zone 2A (Hot - Humid). Get accurate Manual J load calculations with official ASHRAE design temperatures for St. Helena County.
St. Helena County, Louisiana is classified under IECC Climate Zone 2A (Hot - Humid), a cooling-dominated region with humid moisture conditions. With 2 ZIP codes and 1 communities, every HVAC installation in St. Helena County must use the ASHRAE design temperatures of 28°F (99% winter heating) and 97°F (1% summer cooling) for accurate Manual J load calculations.
As a cooling-dominated zone, controlling solar heat gain is essential in St. Helena County. Windows must have an SHGC of 0.25 or lower, along with R-13 wall and R-30 ceiling insulation. Proper sizing prevents oversized AC systems that short-cycle and waste energy.
Minimum insulation R-values and window performance for Climate Zone 2A in St. Helena County, LA.
| Building Component | Minimum Requirement | Unit |
|---|---|---|
| Ceiling / Attic Insulation | R-30 | R-value |
| Wall Insulation | R-13 | R-value |
| Floor Insulation | R-13 | R-value |
| Window U-Factor | 0.4 | BTU/hr-ft²-°F |
| Window SHGC | 0.25 | Coefficient |
| Air Infiltration | 0.25 | ACH50 |
Climate Zone 2A requires precise load calculations. Upload your St. Helena County blueprint and get a professional Manual J report in 60 seconds— first report is FREE. Pre-loaded with St. Helena County's exact design temperatures (28°F winter / 97°F summer).
Enter your ZIP code to confirm it's in St. Helena County and get climate zone details.
Official ASHRAE design temperatures for St. Helena County, LA, used for accurate Manual J load calculations.
Minimum insulation and window requirements for St. Helena County per IECC 2021 energy code.
Climate Zone 2A: Hot - Humid - Cooling-dominated with hot, humid summers and mild winters. Significant cooling loads with moderate heating needs.
1 cities and communities in St. Helena County share Climate Zone 2A requirements.
Compare climate zones with other counties in Louisiana. Different zones require different HVAC equipment sizing.
Upload your St. Helena County blueprint and get a professional Manual J load calculation using official Zone 2A design temperatures. First report is FREE.
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