Case Study: Warehouse Cuts Lighting Energy by 65% with PIR High-Bay Sensors

Overview

A 500,000 square foot distribution center in Illinois was operating 24/7 with all lights on continuously. The facility had 1,500 high-bay LED fixtures (200W each) consuming 300 kW continuously. Annual lighting energy cost was $250,000.

The Challenge

The warehouse faced several specific issues:

• All lights were on 24/7 regardless of activity
• Forklift traffic was concentrated in 30% of aisles at any time
• Loading docks were active only during certain shifts
• Storage areas were visited infrequently
• Manual light switching was impractical (30-foot ceilings)

The Solution

The warehouse implemented a zone-based PIR lighting control system:

• Sensors: OPTEX LX-802 high-bay PIR sensors
• Mounting height: 9m (30 feet)
• Coverage: Each sensor covers 2,000 sq ft (20m x 20m)
• Output: Relay control for LED high bays (on/off)
• Zones: 75 zones (average 10 sensors per zone)
• Quantity: 750 sensors total

Lighting logic:

• Active picking aisles: Lights on at 100% during shift hours, off otherwise
• Storage aisles: Lights on only when motion detected, off after 10 minutes
• Loading docks: Lights on during scheduled shifts, motion override for off-hours
• Office areas: Occupancy sensors with 30-minute hold time
• Restrooms/hallways: Occupancy sensors with 5-minute hold time

The system was integrated with the warehouse management system (WMS) to know which aisles were active based on order picking schedules.

Implementation

The installation was phased over six months:

1. Month 1-2: Active picking aisles (300 sensors, 30 zones)
2. Month 3-4: Storage aisles (350 sensors, 35 zones)
3. Month 5: Loading docks and office areas (100 sensors, 10 zones)
4. Month 6: Integration and testing

Results

After 12 months of operation:

1,300,000

650,000

50%

1,300,000

260,000

80%

260,000

130,000

50%

260,000

130,000

50%

3,120,000

1,170,000

62.5%

$250,000

$93,600

$156,400

表

Additional benefits included:

• Reduced CO2 emissions by 850 metric tons
• Extended LED fixture life (62% fewer operating hours)
• Improved forklift driver visibility (lights only in active aisles)
• Reduced light pollution (warehouse no longer glowing at night)
• Eligibility for utility demand response program ($25,000/year)

Key Lessons Learned

1. High-bay sensors need narrow beams: Standard wide-angle sensors detected adjacent aisles, causing false triggers.
2. Zone-based control is essential: Individual sensor control would have been too complex (750 controllers).
3. WMS integration saved energy: Knowing which aisles were active allowed preemptive lighting.
4. Forklift detection required sensitivity tuning: Slow-moving forklifts were initially missed.
5. Maintenance access needed override switches: Technicians needed to lock lights on during repairs.

Conclusion

This case study demonstrates that high-bay PIR sensors with zone-based control can deliver 62% lighting energy savings in warehouses. The $156,400 annual savings and 18-month payback period made this a successful investment. The key to success was integrating with WMS for active aisle prediction and using narrow-beam sensors.