Built and maintained by a certified ECC Rater. If a value here looks off, it's a bug — every tool reads from the same Python module that drives our compliance pipeline, so a number on a tool page is the number a Title 24 report run would use today.
Climate zone lookup
Find your project's California climate zone (CZ1–CZ16) from its ZIP code. Links straight to the per-zone prescriptive baseline.
Open lookupEnvelope baseline
Side-by-side comparison: prescriptive vs High-Performance Envelope vs Hybrid. Walls, ceiling, roof, windows, HVAC, DHW, PV.
Open toolPV sizer
Required PV size in kWdc for your project. Handles the §150.2(a) scope exemptions and the Exception 2 small-project waiver.
Open calculatorEquipment baseline
Minimum-compliant heating, cooling, and water-heating equipment per climate zone and project scope (NC, Add+Alt, Alteration).
Open toolGlazing checker
Validate a proposed window package against the prescriptive baseline — window-to-floor ratio, U-factor, and per-CZ SHGC.
Open checkerWhy we publish these
Most California Title 24 consultants gate their tooling behind quote requests or paid memberships. We publish the underlying calculations because the values are public — they come from the California Energy Commission's 2025 Energy Code prescriptive tables — and because letting designers and contractors prototype a compliance answer before paying for a report is the right thing to do.
If you build something interesting with one of these tools, or hit a case the calculator gets wrong, let us know.