How it works
Sensors come in three broad types. Under-desk or in-room presence sensors detect whether a desk or room is occupied. Ceiling people counters count how many people are in a zone. Door counters track people entering and leaving a floor or room. Most report anonymously: they count bodies, not identities.
Readings travel over a wireless network to a gateway, then to software that turns them into occupancy by space, hour and day. Running them means power or battery management, network access, mapping each sensor to a space and re-mapping whenever the layout changes.
Sensors and sensorless signals answer different questions. Sensors measure unbookable space precisely but cannot say who was there, so they cannot show team attendance or confirm a specific booking. Presence data from check-ins, network connections and badges covers people and bookings without new hardware. Many organizations use presence data broadly and add sensors only where unbookable space drives decisions.
Occupancy sensor technologies and sensorless signals
Sensor technologies count space; sensorless signals identify people. The right mix depends on the question.
| Technology | What it detects | Strengths | Watch for |
|---|---|---|---|
| Passive infrared (PIR) | Body heat and movement at a desk or in a room | Cheap, low power and anonymous | Misses people sitting still; can read empty after a pause |
| Thermal | Heat shapes, to count people in a zone | Counts people without identifying them | Higher cost; needs ceiling mounting and calibration |
| Radar | Presence, including the small movements of people sitting still | Detects still occupants; anonymous | Higher cost; coverage depends on placement |
| Camera-based | People counts and positions from images | Accurate counts in open areas | Highest privacy concern; prefer devices that keep counts, not images |
| Door counters | People entering and leaving a room or floor | Simple totals by area | Small errors add up over the day |
| Office network presence | Who is in, and on which floor, from devices on the network | No hardware; covers people and teams | Cannot see unbooked zones or people without the software |
| Badge data | Who entered the building or floor, and when | Already collected by access control | Shows entry, not which desk or room was used |
How to measure it
- Start with the questions: team attendance and desk use need presence data; unbookable zones may need sensors.
- Price the full cost: hardware, installation, network, maintenance and re-mapping after moves.
- Pilot on one floor and compare sensor counts with check-ins and network presence.
- Review privacy: prefer anonymous sensors and avoid image capture where you can.
What to check before buying occupancy sensors
- The questions they must answer. Team attendance and desk use need data that knows who was there; unbooked zones need anonymous counts. Choose the technology after the question.
- Total cost of ownership. Price hardware, installation, gateways, batteries, network setup and re-mapping after every layout change, not only the device.
- Network and IT security. IT should review how devices connect, whether they need their own gateway or network segment, how firmware is updated and who can reach the data.
- Privacy by design. Prefer anonymous sensors that store counts, not images. Check what is processed on the device and what leaves it, and involve works councils or employee representatives where required.
- Accuracy in your space. Pilot on one floor and compare readings with check-ins or manual counts before a wider rollout.
- Integration with booking and reporting. Sensor data is most useful next to bookings and attendance. Check the API, and that readings map to the same spaces your booking system uses.
- Maintenance and ownership. Agree who replaces batteries, fixes offline devices and updates the space mapping, and how quickly.
- Sensorless alternatives. Check whether network presence, badge data or automatic check-in already answer the question at lower cost, and add sensors only where they add something.
Examples
- A company uses network presence and desk check-ins for attendance across its offices and adds ceiling counters only in a large collaboration area it plans to redesign.
- A firm moving into a small new headquarters uses automated check-in instead of sensors and spends the savings on furniture.
Benchmarks
Wavex reported saving £20K+ by using automated check-in instead of a sensor deployment in its new London HQ.
Kadence customer story: Wavex
Common mistakes
- Buying sensors before deciding which questions they must answer.
- Treating sensor counts as attendance; sensors cannot tell who was there.
- Forgetting maintenance and re-mapping after every layout change.
- Choosing camera-based sensors without a privacy review.
How Kadence helps
Kadence measures occupancy without sensors: the Kadence Agent checks people in automatically when it detects them on the office network, and Automatic Bookings records people who turn up without a booking. Where other systems already hold presence signals, the public API can check people in to desks and rooms, alongside kiosk, room display and badge check-ins.
Workplace occupancy · WorkOps · Wavex story
Frequently asked questions
How do occupancy sensors work?
Most use passive infrared to detect body heat and movement, or thermal, radar or camera-based counting to count people in a zone. They send readings over a wireless network to software that turns them into occupancy by space and time.
Do you need occupancy sensors?
Not always. If your questions are about attendance, team patterns and desk or room use, check-ins, office network presence and badge data answer them without hardware. Sensors earn their cost in unbookable spaces, or where you need precise counts for a redesign.
What is the difference between sensor and sensorless occupancy?
Sensors measure space directly and anonymously. Sensorless occupancy uses signals that already exist, such as network connections, badge swipes and check-ins, which cover people and bookings but not areas where nobody books or checks in.
Are occupancy sensors a privacy risk?
Anonymous presence and counting sensors carry low risk because they do not identify people. Camera-based sensors carry more, even when they process images on the device. Tell employees what is installed and why, and prefer devices that store counts, not images.
Related terms
- Presence data (sensorless occupancy) The record of who was actually in the building and when, from signals you already have: network, badges and check-ins.
- Badge data Access-control swipe records showing who entered a building or floor and when, often used to measure attendance.
- Occupancy monitoring Continuous measurement of how many people use each building, floor, room and desk, and when, from presence signals or sensors.
- Smart office A workplace that uses connected tools and data, from booking and room displays to presence and building controls, to fit real use.
- Space utilization study A time-bound exercise that measures how desks, rooms and floors are actually used, before a lease, consolidation or redesign.
Kadence editorial team · Last reviewed