South Carolina spans 2 IECC climate zones. Find your exact zone, design temperatures, and get free Manual J load calculations for any South Carolina location.
South Carolina spans 2 IECC climate zones (Zone 2A, Zone 3A), which means insulation requirements, design temperatures, and equipment specs vary significantly depending on location. The primary zone, Zone 2A (Hot - Humid), is cooling-dominated, with winter design temperatures as low as 32°F and summer highs reaching 95°F. HVAC contractors working across South Carolina need to verify the exact climate zone for each job site — using the wrong zone data leads to oversized or undersized equipment, failed inspections, and unhappy homeowners.
Minimum insulation R-values and window specifications required by the 2021 International Energy Conservation Code for South Carolina.
| Component | Zone 2A | Zone 3A |
|---|---|---|
| Ceiling / Attic | R-30 | R-30 |
| Walls | R-13 | R-20 |
| Floor | R-13 | R-19 |
| Window U-Factor | 0.4 | 0.32 |
| Window SHGC | 0.25 | 0.25 |
Source: IECC 2021 Table R402.1.2. Requirements shown are for residential construction. South Carolina contractors must use the zone that corresponds to the job site location.
These ASHRAE design temperatures determine how Manual J load calculations size heating and cooling equipment for South Carolina homes. The winter 99% value represents the coldest temperature expected, while the summer 1% value represents the hottest.
Hot - Humid
Warm - Humid
Based on Climate Zone 2A (Hot - Humid), here are typical HVAC equipment specifications for South Carolina installations.
Annual Fuel Utilization Efficiency for South Carolina furnaces
Seasonal Energy Efficiency Ratio for South Carolina AC systems
South Carolina's climate zone data ensures proper equipment sizing. No more callbacks from oversized or undersized systems.
South Carolina building departments require IECC-compliant Manual J calculations. Our tool uses official South Carolina climate data.
Right-sized systems based on South Carolina climate data reduce energy costs for homeowners and improve your reputation.
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