Wireless occupancy sensor

Sensor technology comparison

Quick comparison of common occupancy sensing technologies and where thermal excels.

PIR (Passive Infrared)

• Detects motion via rapid changes in infrared between object and background.
• Strengths: low cost, low power, effective for motion-triggered lighting.
• Limitations: misses stationary occupants, limited people-counting ability.

Thermal / Heat-based

• Measures infrared energy and heat patterns to detect presence and movement.
• Strengths: anonymous, works in dark/through partial obstructions, better at estimating counts and dwell time.
• Limitations: may be affected by strong ambient heat sources; requires calibration for crowded spaces.

Radar (mmWave)

• Uses radio waves to detect motion and micro-movements.
• Strengths: detects minute motion, can sense through some materials.
• Limitations: potential privacy concerns, more complex signal interpretation.

Camera-based

• Video-based analytics for precise counting and recognition.
• Strengths: high accuracy and rich context.
• Limitations: privacy, higher bandwidth and storage needs, compliance challenges.

When to choose thermal: prioritize privacy, reliable performance in variable lighting, and multi-purpose analytics beyond on/off lighting control.

Use cases for wireless occupancy sensors

• Lighting control: automatic dimming and vacancy-based switching to save energy and extend fixture life.
• HVAC optimization: adjust ventilation and temperature based on actual occupancy to reduce runtime and energy consumption.
• Space utilization: heat-based people counting and dwell analytics to track how meeting rooms and workspaces are used.
• Safety and emergency response: occupancy signals can guide evacuation prioritization and verify cleared areas.
• Workplace analytics: occupancy trends, peak times, and desk utilization without collecting personally identifiable information.

Choosing the right sensor: features to evaluate

Look for these capabilities when evaluating wireless occupancy sensors for commercial buildings:

• Sensing modality: thermal/heat-based if privacy and counting are priorities; PIR for simple motion control.
• Accuracy and latency: documented detection rates and response time for your use case.
• Wireless protocol support: compatible with your lighting controls and BMS (Zigbee, Bluetooth, Wi‑Fi, LoRa, or proprietary RF).
• Power options: battery life estimates, wired low-voltage power, or PoE variants.
• Mounting and coverage: ceiling or wall configurations, field of view, and recommended spacing.
• Integration options: gateways, APIs, BACnet/MQTT support, or native integrations with lighting control platforms.
• Security and privacy: on-device anonymization, encryption of wireless traffic, and clear data retention policies.

Installation and placement best practices

Proper placement maximizes detection accuracy and reduces false triggers.

• Mounting height: ceiling-mount provides broad coverage and better people-counting; wall-mounts can be used for corridor or vestibule detection.
• Spacing: follow vendor coverage recommendations; typical ceiling-mounted spacing ranges vary by sensitivity and room layout.
• Field of view: avoid aiming sensors toward large heat sources (sunlit windows, heaters) and direct HVAC outlets.
• Overlap: allow partial overlap between adjacent sensors to reduce blind spots and improve counting accuracy.
• Calibration and testing: validate detection zones while the space is in typical use and adjust sensitivity as needed.
• Power considerations: if battery-powered, estimate expected battery life based on reporting frequency and feature set. Plan for maintenance access.

Integration and data flow

Wireless occupancy sensors can integrate at several levels:

• Direct control: sensors trigger local lighting or HVAC controllers for immediate response.
• Gateway-based: sensors communicate to a building gateway that normalizes data for multiple systems.
• Cloud analytics: aggregated occupancy data is sent to analytics platforms for reporting, dashboards, and machine-learning models.
• BMS / API integration: support for BACnet, MQTT, REST APIs, or native connectors simplifies enterprise adoption.

When planning integration, review network capacity, security requirements, and how occupancy events map to control logic.

Measuring ROI and typical outcomes

Quantifying benefits helps justify sensor projects. Common measurable outcomes include:

• Lighting energy reduction from vacancy control and dimming strategies.
• HVAC runtime and ventilation savings from demand-based control.
• Real estate efficiency gains through improved space utilization (reduce unused real estate or reconfigure layouts).
• Operational savings from reduced manual checks and automated scheduling.

A pilot deployment in a representative area is the fastest way to measure real-world savings and tune parameters for scale.

Next steps

For commercial deployments, start with a pilot in representative zones to validate coverage, integration, and savings. Evaluate sensors that offer anonymous thermal sensing if privacy and multi-purpose analytics are priorities. If you need help assessing fit or planning a pilot, contact your building systems team or vendor to arrange a site assessment and demo.

FAQs

What is a wireless occupancy sensor?

A device that detects people presence and movement without a wired connection to each sensor, reporting events wirelessly for control or analytics.

How do thermal occupancy sensors differ from PIR sensors?

PIR detects rapid infrared changes (motion) and can miss stationary occupants. Thermal sensors measure heat patterns and are better at detecting presence and estimating counts while remaining anonymous.

Are thermal occupancy sensors anonymous and privacy-safe?

Yes. Heat-based sensors measure temperature patterns rather than capturing images, so they do not record personally identifiable visuals.

Can wireless occupancy sensors integrate with my BMS or lighting controls?

Most commercial wireless sensors support integration via gateways, APIs, or protocols such as BACnet, MQTT, or native control system connectors.

What wireless protocols are commonly supported?

Options include Zigbee, Bluetooth, Wi‑Fi, LoRaWAN, and proprietary RF. Choose sensors compatible with your existing control ecosystem.

How accurate are thermal sensors for people counting?

Accuracy depends on sensor resolution, placement, and scene complexity. Well-placed thermal sensors can reliably estimate counts and occupancy trends for lighting, HVAC, and analytics.

What are typical installation recommendations?

Use ceiling-mount for broad coverage, avoid direct heat sources, follow vendor spacing guidance, and test in normal occupancy conditions.

What is expected battery life or power options?

Battery life varies by reporting frequency and radio type; many wireless occupancy sensors can run multiple years on battery. Wired and PoE power options are available for continuous, maintenance-free operation.