Tulsa County is in IECC Climate Zone 3A (Warm - Humid). Get accurate Manual J load calculations with official ASHRAE design temperatures for Tulsa County.
Tulsa County, Oklahoma is classified under IECC Climate Zone 3A (Warm - Humid), a mixed-climate region with humid moisture conditions. With 66 ZIP codes and 1 communities, every HVAC installation in Tulsa County must use the ASHRAE design temperatures of 17°F (99% winter heating) and 100°F (1% summer cooling) for accurate Manual J load calculations.
With balanced heating and cooling loads, Tulsa 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 3A in Tulsa County, OK.
| 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 3A requires precise load calculations. Upload your Tulsa County blueprint and get a professional Manual J report in 60 seconds— first report is FREE. Pre-loaded with Tulsa County's exact design temperatures (17°F winter / 100°F summer).
Enter your ZIP code to confirm it's in Tulsa County and get climate zone details.
Official ASHRAE design temperatures for Tulsa County, OK, used for accurate Manual J load calculations.
Minimum insulation and window requirements for Tulsa County per IECC 2021 energy code.
Climate Zone 3A: Warm - Humid - Mixed climate with warm, humid summers and cool winters. Balanced heating and cooling needs.
1 cities and communities in Tulsa County share Climate Zone 3A requirements.
Compare climate zones with other counties in Oklahoma. Different zones require different HVAC equipment sizing.
Upload your Tulsa County blueprint and get a professional Manual J load calculation using official Zone 3A design temperatures. First report is FREE.
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