Arkansas is in IECC Climate Zone 3A (Warm - Humid). Get accurate Manual J load calculations with official design temperatures and IECC requirements.
Arkansas falls entirely within IECC Climate Zone 3A (Warm - Humid), making it a mixed-climate state requiring careful balance between heating and cooling equipment sizing. With a winter 99% design temperature of 22°F and a summer 1% design temperature of 94°F, Arkansas HVAC contractors must size systems for a 72°F temperature swing between extreme winter and summer conditions. Proper Manual J load calculations using these design temperatures are essential for code-compliant, right-sized installations that avoid callbacks and comfort complaints.
Minimum insulation R-values and window specifications required by the 2021 International Energy Conservation Code for Arkansas.
| Component | Zone 3A |
|---|---|
| Ceiling / Attic | R-30 |
| Walls | R-20 |
| Floor | R-19 |
| Window U-Factor | 0.32 |
| Window SHGC | 0.25 |
Source: IECC 2021 Table R402.1.2. Requirements shown are for residential construction.
These ASHRAE design temperatures determine how Manual J load calculations size heating and cooling equipment for Arkansas homes. The winter 99% value represents the coldest temperature expected, while the summer 1% value represents the hottest.
Warm - Humid
Based on Climate Zone 3A (Warm - Humid), here are typical HVAC equipment specifications for Arkansas installations.
Annual Fuel Utilization Efficiency for Arkansas furnaces
Seasonal Energy Efficiency Ratio for Arkansas AC systems
Arkansas's climate zone data ensures proper equipment sizing. No more callbacks from oversized or undersized systems.
Arkansas building departments require IECC-compliant Manual J calculations. Our tool uses official Arkansas climate data.
Right-sized systems based on Arkansas climate data reduce energy costs for homeowners and improve your reputation.
Upload your Arkansas blueprint and get a professional Manual J load calculation with official climate zone data. First report is FREE.
Join 10,000+ Arkansas contractors who trust AutoHVAC for permit-ready load calculations
Get detailed climate zone information for major cities
Need Arkansas HVAC permit forms and building department contacts?
View Arkansas Permit Directory