Randall County is in IECC Climate Zone 4B (Mixed - Dry). Get accurate Manual J load calculations with official ASHRAE design temperatures for Randall County.
Randall County, Texas is classified under IECC Climate Zone 4B (Mixed - Dry), a mixed-climate region with dry moisture conditions. With 8 ZIP codes and 1 communities, every HVAC installation in Randall County must use the ASHRAE design temperatures of 14°F (99% winter heating) and 96°F (1% summer cooling) for accurate Manual J load calculations.
With balanced heating and cooling loads, Randall County homes require well-rounded insulation — R-20 walls, R-49 ceilings, R-19 floors — and windows with both U-factor 0.32 and SHGC 0.4 to handle both winter lows and summer highs.
Minimum insulation R-values and window performance for Climate Zone 4B in Randall County, TX.
| Building Component | Minimum Requirement | Unit |
|---|---|---|
| Ceiling / Attic Insulation | R-49 | 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 | 0.4 | Coefficient |
| Air Infiltration | 0.15 | ACH50 |
Climate Zone 4B requires precise load calculations. Upload your Randall County blueprint and get a professional Manual J report in 60 seconds— first report is FREE. Pre-loaded with Randall County's exact design temperatures (14°F winter / 96°F summer).
Enter your ZIP code to confirm it's in Randall County and get climate zone details.
Official ASHRAE design temperatures for Randall County, TX, used for accurate Manual J load calculations.
Minimum insulation and window requirements for Randall County per IECC 2021 energy code.
Climate Zone 4B: Mixed - Dry - Mixed climate with low humidity, warm summers and cold winters. Significant heating and cooling needs.
1 cities and communities in Randall County share Climate Zone 4B requirements.
Compare climate zones with other counties in Texas. Different zones require different HVAC equipment sizing.
Upload your Randall County blueprint and get a professional Manual J load calculation using official Zone 4B design temperatures. First report is FREE.
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