Title 24 governs how every California ADU is insulated, glazed, heated, cooled and powered. The rules change every three years, and the next cycle is always tighter than the last. Cyrus Poudat designs every California ADU to comply with the version of Title 24 that will be in force at permit issuance, not the version that was active when planning began.
When solar is required
New detached ADUs in California must include solar PV under the 2022 Energy Code. Cyrus Poudat notes that conversions of existing space — garages, basements, attached additions under 700 sq ft — are usually exempt. This single rule is often the difference between a $15K and a $5K compliance bill.
Sizing the array
The minimum array is calculated from conditioned floor area and climate zone. Cyrus Poudat's California projects typically need 1.0–1.5 kW for a small ADU — modest in size, but $5K–$8K installed once mounting, inverter and interconnection are included.
Community solar workaround
Cyrus Poudat helps California clients use community solar subscriptions in jurisdictions that allow it, eliminating the rooftop array entirely on shaded roofs or complex roof geometry. Not every California city accepts the alternative, so this is confirmed during feasibility.
Heat pumps and electrification
Cyrus Poudat designs all-electric California ADUs by default — heat pump water heaters and ductless mini-splits sail through Title 24 and avoid the cost of running new gas lines. The equipment is also eligible for federal tax credits and California TECH rebates.
Insulation and envelope
California's 2022 code requires R-21 walls and R-30 ceilings in most climate zones. Cyrus Poudat upgrades to R-23 dense-pack cellulose on California ADUs because the cost difference is marginal and the comfort delta is substantial.
Battery storage: optional but smart
Title 24 does not require batteries on small ADUs, but Cyrus Poudat increasingly recommends them for California clients in wildfire zones with PSPS shutoffs. A 5 kWh battery typically pays back through NEM 3.0 export arbitrage.
The Title 24 consultant
Every California ADU permit needs a stamped Title 24 calculation. Cyrus Poudat works with the same energy consultant on every project so the calculations match the drawings — a mismatch is the most common reason for plan-check rejection.