Insulation R-values required in IECC climate zone 3 — attic, walls, and floor
What the 2021 IECC requires in climate zone 3: insulation for the attic, walls, and floor. A thicker layer means a higher R-value.
What this diagram shows
A house cross-section showing the 2021 IECC minimum insulation R-values for climate zone 3 (warm): the required R-value for the attic or ceiling, the exterior walls, and the floor, with each layer drawn thicker where a higher R-value is required. Climate zone 3 covers the Deep South, central Texas, and the low-desert Southwest. Values are from IECC Table R402.1.3.
Related diagrams
Insulation & ClimateMap of the eight IECC climate zones across the United States
Insulation & ClimateWhy IECC climate zones are assigned by county, not by state or city
Insulation & ClimateIECC minimum attic and wall R-values across all eight climate zones
Insulation & ClimateWhat R-value means — the same R-30 takes very different thickness by material