Occupancy sensors: Title 24 required, energy effective.
Occupancy and vacancy sensors automate lighting on/off based on space occupancy. Required by Title 24 in most commercial spaces; deliver 15-30% energy savings on lighting circuits.
By Steven Lockhart · Reviewed by Alex Towery, C-10 #989290
Updated 2026-06-16
Occupancy/vacancy sensor installation: ceiling-mount or wall-mount sensors detect motion or absence-of-motion, control lighting circuits automatically. Title 24 requires occupancy or vacancy sensors in most commercial spaces with specific delay timing requirements. Sensor types vary by detection technology (PIR, ultrasonic, dual-tech) and mounting (ceiling, wall, fixture-integrated). Per-sensor cost $80-$240 installed; deliver 15-30% lighting energy savings in occupancy-variable spaces.
01Occupancy vs vacancy — what's the difference.
Occupancy sensors automatically turn lights ON when motion detected and OFF when motion stops (after delay). Auto-on behavior is convenient for corridors, restrooms, storage rooms where hands-free operation matters. Vacancy sensors only turn lights OFF automatically — they require manual ON. More energy efficient (lights only on when explicitly desired). Title 24 prefers vacancy sensors in most spaces.
Space-type guidance: vacancy sensors in offices, conference rooms, private workspaces — manual-on respects user preference. Occupancy sensors in corridors, restrooms, storage areas, parking areas — automatic-on appropriate for transient occupancy. Both meet Title 24 with proper configuration; preference depends on space function.
02Three sensor technology types.
Passive Infrared (PIR)
Detects heat signature movement. Most common technology. Reliable in spaces with clear line-of-sight. Limitations: doesn't detect through partitions, sensitive to HVAC airflow in some installations.
Ultrasonic
Detects motion via sound wave reflection. Works through partitions and around partial obstructions. Limitations: false triggers from HVAC, sensitive to small movements far from sensor.
Dual-tech (PIR + Ultrasonic)
Combines both technologies — requires both to confirm presence/absence. Most reliable, fewer false triggers. Higher cost ($120-$240 per sensor vs $80-$150 for single-tech). Standard for premium commercial applications.
03Common installation considerations.
Sensor placement matters significantly. Ceiling sensors centered in spaces with clear sightlines work well; corner-mounted sensors with restricted view sometimes miss occupants. Wall-mount sensors at switch locations practical for retrofit; ceiling-mount sensors for new construction. Coverage patterns specified per sensor type — match coverage to room geometry during design.
Wiring scope: sensors connect between lighting circuit and the controlled fixtures. Standalone sensors handle small spaces (single rooms); networked sensors required for larger spaces or multi-zone control. Most retrofit installs use standalone sensors; new construction increasingly uses networked control for whole-building optimization.
Common questions.
Are occupancy sensors required by code?
Yes — Title 24 requires occupancy or vacancy sensors in most enclosed commercial spaces. Specific requirements vary by space type. Required for permit closure on new construction and substantial retrofit projects.
How much do sensors save?
Typical savings: 15-30% reduction in lighting energy use for spaces with variable occupancy (conference rooms, restrooms, private offices). Higher savings in spaces with sporadic occupancy (storage rooms, mechanical rooms). Lower savings in spaces with steady occupancy (open office during business hours).
What about sensor false triggers?
Quality dual-tech sensors with proper configuration have minimal false triggers. Single-tech PIR sensors can false-trigger from HVAC airflow or solar warming through windows; ultrasonic from HVAC noise. Configuration adjustment usually resolves; dual-tech eliminates most issues.
How do you handle pricing — flat fee or hourly?
Both, depending on scope. Routine service calls and predictable scope (panel replacement, EV charger install, transfer switch install, fixture replacement) are flat-fee quoted up front. Diagnostic visits and emergency scope are hourly because we don't know what we'll find. Either way, you get a written quote before work starts on anything significant, and we don't proceed beyond the quote without your sign-off.
How quickly can you schedule?
Depends on scope and season. Emergency dispatch: same-day across Marin County (1-3 hours business hours, 1-4 hours after-hours). Same-day standard service: 3-6 hours from call when capacity allows; otherwise next business day. Scheduled service work: 1-3 weeks typical. Larger projects requiring permits and PG&E coordination: 4-12 weeks depending on scope. We're upfront about timeline at the quote stage.
What warranty do you offer on work?
Our standard residential warranty: 2 years on labor, manufacturer warranty on parts (varies by product — typically 1-10 years). Major installs (panels, generators, EV chargers) often have longer manufacturer warranties (5-10 years). If there's an issue with our work in the warranty period, we come back and fix it at no cost. We also stand behind work past warranty — repeat customers and referrals matter more than a transactional fix.
Are you licensed and insured?
Yes. California State License Board C-10 Electrical Contractor #989290, in good standing. Carry general liability insurance and workers' compensation insurance as required by California law. Bondable on projects requiring it. Happy to provide proof of insurance to clients or property managers on request. License lookup: cslb.ca.gov.
Talk to a licensed electrician in Marin.
Family-run, C-10 #989290, 20+ years in the trade. Honest scoping, fair pricing, work that lasts.