Kirsten Robinson Novakoski
Nov 10, 2025
Starting January 1st, 2026, what is expected of project's under the updated code cycle.
The updated 2025 California Energy Code focuses on electrification-readiness, tighter building envelope standards, and improved efficiency for lighting and mechanical systems. Projects permitted after the January 1st, 2026 cut-off can expect new baselines for mandatory requirements, updated values for prescriptive (forms-based) compliance, and a rebranding of the energy metrics for performance-based energy modeling under the new code cycle.
2025 code cycle updates are summarized at a high level below.
Envelope
Mandatory insulation levels:
Single-family: Reduced mandatory wall insulation in framed assemblies and lower maximum weighted average U-factor for fenestration (including skylights).
Nonresidential and Multifamily: New maximum U-factor for new and altered fenestration.
Prescriptive requirements:
Single-family: Increased insulation for cathedral ceilings and reduced maximum vertical fenestration U-factor.
Nonresidential and Multifamily: Reduced maximum roof and exterior wall U-factors for all climate zones.
Solar PV and Battery Energy Storage (BESS)
2025 updates have impacted the calculation of the prescriptive (forms) and Standard building (used in performance approach) solar PV and BESS sizes.
Updated conditioned floor area factors resulting in higher prescriptive PV capacities for retail/grocery, restaurant, library, medical office, clinic, and hotel/motel building types.
Revised battery size calculation and added adjustment pathway for projects restricted by the SARA method for PV sizing.
New exceptions for single family battery ready requirements.
Mechanical, Plumbing, and Electrical Systems
Mandatory requirements:
Updated system efficiency baselines.
Revised ventilation calculations.
New laboratory exhaust requirements.
Electric ready requirement for commercial kitchens with gas equipment.
Exhaust-driven multifamily ventilation is no longer allowed.
Single family system sizing updates.
Updated pipe insulation requirements.
Heat pump ready requirements.
Pool and spa heaters restricted to heat pump or renewable based systems.
Prescriptive requirements:
Offices and school buildings ≤150,000sf and ≤5 stories have limited system options for prescriptive compliance.
Simultaneous mechanical heat recovery is required in new buildings meeting a certain heating and cooling capacity threshold.
Multifamily buildings can only meet prescriptive requirements with balanced ventilation.
Gas space heating and DHW heating in single family homes is no longer allowed prescriptively.