How does Title 24 affect lighting?

Title 24 requires that lighting in a new ADU be high-efficacy — in practice, LED — and that certain spaces include automatic controls such as dimmers, vacancy/occupancy sensors, or daylighting controls. The goal is to minimize wasted lighting energy without limiting how well-lit your ADU is.

The core lighting rules

• High-efficacy sources. Permanently installed luminaires must be high-efficacy. Modern LED fixtures and LED retrofit assemblies easily satisfy this; older incandescent or halogen sources do not.
• Controls in key spaces. The code requires specific controls depending on the room — for example, dimmers or vacancy sensors in many indoor areas, and occupancy/motion or photocontrols for certain exterior fixtures so lights don't burn during daylight or when a space is empty.
• Recessed fixtures. Recessed luminaires in insulated ceilings must be airtight and insulation-contact (IC) rated to limit air leakage through the envelope.
• Exterior lighting. Outdoor fixtures generally need to be high-efficacy and controlled (motion sensor plus photocontrol, or an astronomical time switch).

Lighting power density and the bigger picture

Residential Title 24 leans on these source and control requirements rather than the heavy lighting-power-density calculations seen in commercial work, but the underlying intent is the same: cap unnecessary lighting energy. Because lighting interacts with the whole-building model, your fixture and control choices can also affect a performance-path CF1R, where strong lighting efficiency can help offset weaker performance elsewhere.

How it appears on your electrical plans

Your electrical plans carry this through with a lighting layout, a fixture schedule noting high-efficacy/LED fixtures, and notation for required dimmers, vacancy sensors, and exterior controls. A typical ADU lighting checklist looks like this:

1. All permanent fixtures specified as high-efficacy LED.
2. Dimmers or vacancy sensors shown where required by room type.
3. Recessed cans called out as airtight and IC-rated.
4. Exterior fixtures with motion sensor and/or photocontrol.
5. Fixture schedule consistent with the CF1R assumptions.

Missing control notation — for instance, no vacancy sensor where one is required, or exterior lights without a photocontrol — is an avoidable plan-check correction we head off by aligning the CF1R and the electrical sheets.

The applicable code cycle and local amendments vary — confirm with your local building department. Our Title 24 add-on (+$240) is prepared alongside your electrical and full MEP plans so lighting requirements are reflected consistently across both.