Measure Overview
This measure proposes the following revisions to the mandatory control requirement section in the code (Section 130.1) and the associated acceptance test (NA 7.6 in the Reference Appendices). The proposed changes include both updates in the requirements and code language clean-up. Many of the proposed measures also bring the requirements in Title 24, Part 6 in better alignment with the national standards (ASHRAE 90.1) and other model codes (IECC).
- Require nighttime dimming in parking garage daylight adaptation zones. This measure ensures proper visual adaptation for drivers entering parking garages at night by requiring lighting in the daylight adaptation zones to reduce the light level to that of the general parking zone from sunset to sunrise.
- Require partial or full OFF occupant sensing controls in more spaces. The space types currently being considered include lounges, breakrooms, waiting areas, auditorium areas, hotel function areas, financial transaction areas, lobbies in certain building types, museum exhibition/display areas, and rooms that houses server racks in data centers. Additionally, the requirement would trigger occupied standby controls in spaces where ventilation is allowed to be shut off and temperature set back when no occupant is detected. This would result in energy savings from HVAC systems.
- Reduce occupant sensing control time delay to 15 minutes. This measure would reduce the time delay for occupant sensing controls from the current 20 minutes to 15 minutes.
- Clarify the definition and reduce the threshold for requiring multilevel lighting controls. This code change would improve the definition of multilevel lighting controls to clarify their relationship with continuous dimming and other mandatory control requirements. Additionally, the measure proposes lowering the current 0.5 watts per square foot threshold for requiring multilevel lighting Proposal Summary 2 controls. The tentative new threshold is 0.4 watts per square foot, but the final value will be determined based on a more careful cost-effectiveness analysis.
- Require continuous dimming for daylight responsive controls regardless of the lighting code Section 130.1(b) multilevel lighting controls exception. This proposed measure aims to resolve confusion and additional complexity between two interrelated mandatory control requirements and their exceptions, thereby enhancing code clarity and enforceability. This proposed change would require multilevel lighting controls as long as daylight responsive controls are required in a space.
- Require manual overrides of daylight responsive controls to be timed or reset at the next ON cycle. The proposed measure would require overrides to daylight responsive controls to either have a set time limit or be canceled the next time the lights are turned on again after being turned off by manual switching, time-based controls, or occupant sensing controls.
- Make the Alternate Partial Daylight Test the only test method for the Daylight Responsive Control Acceptance Test. This proposed measure would remove the Partial Daylight Test method and make the Alternate Partial Daylight Test the only test method. This simplify the acceptance test procedure and promote better compliance with the daylight responsive controls requirements.
- Improve the lighting controls acceptance test methods for luminaire-level lighting controls (LLLC). The proposed measure would improve the acceptance test methods by providing instructions for testing LLLCs when they are used as the control solution to meet the mandatory lighting controls requirements. The improved test method would reduce test burden and increase effectiveness for the Acceptance Test Technicians.
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This measure page will be updated as the 2028 code cycle progresses. For questions or suggestions, submit feedback to [email protected]. Please include the measure name in the subject line.
View the Energy Commission's proceedings and available proposed code language by visiting their CEC 2028 Proceedings Website page.
Scope of Proposed Code Change
| Building Type(s) | Construction Type(s) | Type of Change | Updates to Compliance Software | Third Party Verification |
| Nonresidential, Multifamily | New construction, additions, alterations | Mandatory | Update existing feature, add new feature | Update existing verification requirements, add new verification requirements |
Justification for Proposed Change
Several of the proposed revisions to the mandatory control requirements would bring Title 24 into alignment with ASHRAE 90.1 lighting requirements and increase energy savings. The nighttime adaptation compensation controls for the parking garage daylight adaptation zone are an existing requirement in ASH RAE 90.1, and such controls are considered a best practice to increase safety from an illuminating engineering standpoint. ASHRAE 90.1 also requires more spaces to implement partial or full OFF occupant sensing controls, and some of those spaces are currently either not required to have occupant sensing controls or not included as an area category in Title 24. Reducing the occupant sensing control time delay to 15 minutes is also currently being proposed as part of the 2025 code update cycle for ASH RAE 90.1, which provides a good opportunity for Title 24 to adopt the same requirements.
The 0.5 watts per square foot threshold for requiring multilevel lighting controls has been in place since the pre-LED era and was based on traditional light sources. With LEDs’ high efficacy and being continuously dimmable with no or minimal additional cost, it would be prudent to recalibrate and revise the threshold based on current technologies. Furthermore, the code language for multilevel lighting controls has been ambiguous as to whether it pertains to continuous dimming that other controls can utilize or a physical dimmer for manual dimming. Since several other mandatory control sections reference multilevel lighting controls, it is essential to clean up the multilevel lighting controls code language to ensure those references are consistent and coherent. The current exception for multilevel lighting controls also creates a conflict with daylight responsive controls when a space is exempted from multilevel lighting controls but is required to implement daylight responsive controls. Without continuous dimming provided by multilevel lighting controls, daylight responsive controls would not be effective, and the resulting behavior could be perceived negatively by the occupant. The proposal of requiring continuous dimming for daylight responsive controls regardless of the multilevel lighting controls exception aims to address this conflict.
Requiring manual overrides of daylight responsive controls to be timed or reset at the next ON cycle is a code cleanup effort to address ambiguity in the current code language that does not clearly specify whether daylight responsive controls can be overridden by any user and how and when daylight responsive controls should resume when overridden.
The Alternate Partial Daylight Test was proposed and adopted in the 2022 T24 energy code as an alternative to the original Partial Daylight Test, as creating a proper test condition for performing the original Partial Daylight Test is often difficult. The intent was for the two test methods to coexist for a few code cycles, allowing Acceptance Test Technicians’ (ATTs’) to make a smooth transition to the Alternate Partial Daylight Test. It is time to formally remove the less effective Partial Daylight Test to improve acceptance test effectiveness and increase the compliance rate.
Current lighting controls acceptance test methods were designed for zone-based controls, where the lights in the entire zone, e.g., a daylit zone, are controlled by a single sensor. When luminaire-level lighting controls (LLLC) are used as the control solution to meet mandatory control requirements, the sampling rules in current test methods create a test burden, as too many controls would need to be tested. Additionally, the current test methods needs to consider the independentedness of each LLLC luminaire in responding to changing daylight conditions and provide specific instructions for correctly and effectively performing the Full Daylight Test.
Relevant Documents
Round One Utility-Sponsored Stakeholder Meeting Materials
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The Statewide CASE Team values input from all stakeholders engaged in the Title 24, Part 6 code change process. We encourage the open exchange of code change comments and concerns.