Short answer
Title 24 is California's energy code; it governs how efficiently your new HVAC system must be installed. The A2L change is a federal rule about the refrigerant inside new equipment. They're separate, but both apply to a modern changeout — and your installer handles both.
What Title 24 is
Title 24 refers to California's Building Energy Efficiency Standards, part of the state building code. It sets energy requirements for new buildings and for many alterations — including replacing heating and cooling equipment. It's updated on a multi-year cycle, so the exact measures evolve over time.
When you replace a system, applicable Title 24 measures can touch things like equipment efficiency, correct sizing, and duct integrity. Which ones apply depends on your specific project and jurisdiction.
What the A2L refrigerant change is
Separately, federal rules under the AIM Act are phasing down high global-warming-potential refrigerants. New air conditioners and heat pumps now use A2L refrigerants — mainly R-454B and R-32 — instead of R-410A. We cover the homeowner impact in detail in "Do I have to replace my R-410A AC?".
How they intersect on a real job
On a new installation, both rules apply at once but in different lanes:
- A2L (federal): determines the refrigerant your new equipment uses.
- Title 24 (state): determines the energy-efficiency requirements of the install.
A properly installed modern system satisfies both. Compliance is documented through the permit and confirmed at inspection.
[GATHER: confirm which Title 24 measures and verification steps apply for SLO County, Santa Barbara County, and the relevant cities, plus any current code-cycle specifics.]
What it means for you
You don't need to memorize the code — you need an installer who pulls the permit, meets Title 24, and uses compliant A2L equipment. That's what we do. If you're still deciding whether to replace at all, start with the R-410A guide or compare heat pump vs. furnace.