How the lookup works
The California Energy Commission publishes a ZIP-code-to-climate-zone map; we mirror that data and resolve your ZIP to one of the 16 California climate zones in real time. The result includes a link to the prescriptive baseline page for that zone — wall and ceiling R-values, window U-factor and SHGC, HVAC efficiency, and required water-heater type.
Why your ZIP code matters
Every Title 24 prescriptive value changes by climate zone. Two homes 50 miles apart in California can have entirely different code-minimum specs for windows, insulation, and HVAC. Knowing the zone before you start the compliance process saves you from over- or under-specifying equipment. See the climate zones overview for what changes between them.
Browse all 16 zones
CZ1 · CZ2 · CZ3 · CZ4 · CZ5 · CZ6 · CZ7 · CZ8 · CZ9 · CZ10 · CZ11 · CZ12 · CZ13 · CZ14 · CZ15 · CZ16