2026 Lighting Code Updates: California Title 24 and ASHRAE 90.1

Complying with government regulations and other building construction codes requires staying informed of the regular updates. Lighting regulations mandate fixtures, controls and energy standards throughout the lighting industry. Energy regulations aim to conserve energy, improve efficiency and safety for new construction and remodel, commercial and residential developments.

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) maintains a national U.S. standard, which many states use to enact energy policy. ASHRAE, Illuminating Engineering Society (IES) and American National Standards Institute (ANSI) collaborate to publish certain standard updates. For building energy efficiency, California’s Title 24, Part 6 is published and maintained by the California Energy Commission (CEC). The CEC develops the standards, updates them on a three-year cycle, and adopts them into California’s Building Energy Efficiency Standards. The current 2025 standards became effective on January 1, 2026. Because California is such a large construction and lighting market, manufacturers often design products to satisfy Title 24’s stringent requirements. Features that were once unique to California—such as advanced occupancy sensors, daylight harvesting, high-end dimming controls, and demand-responsive lighting controls—have gradually become common across North America.

ASHRAE Updates

ASHRAE included a series of addenda to the existing 90.1-2022 standard. Accordingly, designers and engineers ought to review ASHRAE’s Light Power Density (LPD) updates. Previous LPD Table 9.5.1.2-1 is now split into tables in sections 9.4 and 9.5.2 to separately address power and controls. Updates to Light Loss Depreciation (LLD) and luminaire efficacy (two percent increase) result in a 6.5 percent average reduction in space-by-space LPD values.

In section 9.4, apart from various updates to technical errors and terminology, there are also changes to controls requirements. For certain spaces where use is not common, local controls and multilevel control requirements have been removed. Automatic reduction control is also added in space types to restrict lighting energy. New lighting controls now apply to some healthcare facilities with an aim to reduce lighting to accommodate human circadian rhythm. 

Controls for office spaces larger than 300 square feet are further defined. Occupancy sensor time delay is reduced from 20 to 15 minutes, mandating a two to five percent energy reduction. Newly imposed provisions are intended to close loopholes.

ASHRAE added new controls to exit-related lights, reducing building exit access lighting power allowance from 0.02 W/ft² to 0.01 W/ft² across the lighted floor area.

Energy controls for daylight are also stricter. Wattage for automatic daylight response controls for sidelighting areas for conditions where there is not much power went down. Combined primary and secondary sidelight daylight area wattage is now standardized to 75 watts each predicated on controllability and use of LED multilevel lighting. The minimum value of lighting power by automatic daylight responsive control system is halved from 20 percent to 10 percent power (Section 9.4.1.1).

ASHRAE 90.1 is a model energy standard, so its requirements apply only when the relevant edition has been adopted by the governing jurisdiction. Consult state and local regulations for your project, which may be more or less strict.

Additional Restrictions in California’s Title 24

In 2026, Title 24 adds new restrictions on lighting power, fixtures and controls (including daylighting). Refer to building energy efficiency controls on the official Title 24 government regulation site. Use the link to review California lighting regulation.

Notable changes

• Changes to indoor Lighting Power Allowance (LPA) and Power Adjustment Factor (PAF), section 140.6.
  • The Complete Building Method (on page 338) and the Area Category Method (on page 341) still determine the state’s Lighting Power Allowance. Review Area Category Method for updates to individual space type power allowance. Additional Lighting Power Allowances are available for certain individual space types and may be noted on the right Table 140.6-C column.
• The state eliminates the Tailor method as compliance method. Wattage flexibility is now offered in additional allowances to Area Category Method.
• All government-allowed illuminated sign lighting must now be LED or neon fixtures.

Controls

• Power Adjustment factors for daylighting and occupancy sensor controls are found on page 333 Table 140.6-A. 
• Manual Area control section 130.1(a)2 (on page 260) are changed. Manual controls must now be located in the same space or visible from space.
• Table 130.1A has been eliminated. Multi-level lighting must have continuous dimming to 10 percent or lower. Legacy HID or induction light sources are exempt from full continuous dimming, but are required to provide at least one control step between 30 and 70 percent of full rated power.
• Primary, secondary and skylit indoor daylit zone wattage has been changed from 120 to 75 watts. (130.1d)
• If a primary daylit zone is not required and secondary daylit zone is less than 85 watts, daylighting controls for secondary zones are now exempted (130.1d).

Conclusion

These updates to ASHRAE/IES/ANSI and Title 24 include notable changes. Updates made in 2025 are in effect for 2026 and must be followed for government energy compliance. Individual space type requirements, including additional allowances, should be reviewed for specific power allowance requirements. Minimizing energy usage through lighting wattage and controls design is mandated to save energy and lower the carbon footprint while providing cost savings. These changes are intended to improve lighting efficiency through controls while supporting a better experience within these spaces.

Sources:

California Energy Commission. 2025 Building Energy Efficiency Standards [PDF].

ASHRAE/IES/ANSI. Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings.

ASHRAE/IES/ANSI. Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings, Addenda 1.

ASHRAE/IES/ANSI. Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings, Addenda 2.

ASHRAE/IES/ANSI. Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings, Addenda 3.