Under California's Title 24 Energy Code, which lighting control requirement applies to residential buildings with ceiling-mounted luminaires in rooms larger than 70 square feet?
Correct Answer
B) Vacancy sensors or multilevel switching is required
Title 24 Part 6 Section 150.0(k) requires vacancy sensors or multilevel switching for ceiling-mounted luminaires in residential rooms larger than 70 square feet. This energy efficiency measure helps reduce unnecessary lighting consumption by automatically turning off lights when spaces are unoccupied or providing multiple light levels.
Why This Is the Correct Answer
Title 24 Part 6 Section 150.0(k) requires that ceiling-mounted luminaires in residential rooms larger than 70 square feet be controlled by vacancy sensors or multilevel switching (e.g., dimmers or multi-scene controls). Vacancy sensors turn lights off automatically when a space is unoccupied but require manual turn-on (unlike occupancy sensors, which turn on automatically). Multilevel switching provides at least two light levels (typically 50% and 100%), reducing energy use when full illumination is not needed.
Why the Other Options Are Wrong
Option A: Motion sensors are required in all rooms
Motion sensors (occupancy sensors) are not universally required in all residential rooms under Title 24. The code specifies vacancy sensors or multilevel switching for the rooms in question — not automatic-on motion sensors, which are better suited to spaces like bathrooms or stairwells.
Option C: Dimmer switches must be installed on all lighting circuits
Dimmer switches alone do not satisfy the Title 24 requirement unless they are part of a qualifying multilevel switching system. A simple dimmer that can be set to any level does qualify as multilevel if it meets the code's definition, but the question frames dimmers as the exclusive option rather than one of two acceptable compliance paths — making this answer incomplete and misleading.
Option D: Automatic daylight controls are mandatory
Automatic daylight controls (photosensors/daylighting controls) are required in certain commercial and large residential applications under Title 24, but they are not the primary requirement for ceiling-mounted luminaires in rooms over 70 square feet in residential buildings. Daylight controls are more relevant to skylights and fenestration requirements.
Memory Technique
Remember '70 sq ft = the size of a small bedroom.' Any room big enough to be a real room (over 70 sq ft) needs smart lighting controls under Title 24. The two compliant options are **V**acancy sensors or **M**ultilevel switching — **VM** like a 'Volt Meter' for energy efficiency.
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