Sensor Lights for Commercial Buildings
Last updated: 30 June 2026
PIR and microwave built the market — but thermal, mmWave radar and time-of-flight sensors are changing it. A plain-English guide by use case, with a sensor-type recommendation table and the AS/NZS rules that govern each.
For nearly thirty years, two sensor types ran the entire commercial lighting market: passive infrared and microwave. If a light in your office, warehouse or stairwell switched itself off when nobody was around, one of those two was behind it. They are cheap, proven, however, both have their limitations.
Why this matters
Occupancy sensing is one of the cheapest energy levers in a building. Switching or dimming lights when a space is empty typically cuts lighting energy by up to 30% in offices, and far more in intermittently-used spaces like warehouse aisles, car parks and back-of-house areas. It is also no longer optional. The National Construction Code (NCC) Section J requires that 95 per cent of the lighting load in most spaces larger than 250 m² is controlled by a time switch or an occupancy sensor.
So the question is not whether to use sensors — it is which sensor, in which space. Get it wrong and you get the two complaints every facilities manager knows: lights that drop out while people are still working, and lights that never switch off because the sensor triggers on a passing forklift or a gust through a roller door. We covered the basics of this in our an earlier knowledge-centre article on sensor lights; this piece updates it for the sensor types now available in the market.
The two incumbents — and their blind spots
Passive infrared (PIR)
PIR detects the heat of a moving body crossing its field of view. It is inexpensive, sits outside the fitting, and works well in enclosed spaces where it has clear line of sight — private offices, meeting rooms, toilets. Its weaknesses are well known: it misses a still person (someone reading or on a long call), it struggles to see someone walking straight towards it rather than across it, and it goes under-sensitive when the background is warm. Dust and grime on the lens degrade it over time.
Microwave (high-frequency)
Microwave sensors emit a high-frequency signal and measure the echo, so they pick up far smaller movements than PIR and can see through thin partitions and around objects, covering roughly an 8 m radius from the fitting. The flip side is over-triggering: untuned, a microwave sensor will hold the lights on for any moving object nearby — a swinging door, a fan, traffic the other side of a plasterboard wall. In a warehouse or car park that sensitivity is a feature; in a quiet office it is a nuisance that has to be dialled back.
The new generation
Thermal (low-resolution infrared imaging)
Newer thermal sensors build a coarse heat image of a space rather than just reacting to movement. Because they read shape and direction, they can tell a person from a forklift, count how many people are present, and — critically — hold the lights on for someone sitting perfectly still. The resolution is deliberately too low to identify anyone, so no recognisable image is ever stored, which sidesteps the privacy objection that kills camera-based counting. The same heat image can flag a motor or switchboard running hot for predictive maintenance. Our own view, and the direction the market is heading, is that thermal may eventually replace both PIR and microwave as the cost comes down.
Millimetre-wave (mmWave) radar
mmWave radar detects micro-movements as small as the rise and fall of breathing, which makes it excellent at confirming a stationary person is still there. It works in any light and through thin barriers. Like microwave, it needs tuning to stop it reacting to movement outside the intended zone, but its presence-detection accuracy is a clear step up from PIR, especially in areas with special requirements or challenging environments.
Time-of-flight (ToF) and infrared arrays
Time-of-flight sensors fire an infrared pulse and measure how long it takes to return, building a depth map of the space. Independent research (Energy and Buildings, 2021) has shown occupancy-counting error rates as low as around 0.4 per cent. They are privacy-preserving, cover roughly 10 m, and are strong for accurate people-counting. Due to cost and commissioning requirements, they are currently recommended for specialist areas only.
Sensor recommendations by use case
Sensor selection depends on the space, the way people move through it, environmental conditions, and the standard that governs it. Here is the short version.
Use case / space | Recommended sensor type | Why it works here | What to watch out for | Governing standard |
Office / meeting rooms | Thermal or PIR + mmWave | Holds lights on for still, seated occupants; no false drop-outs mid-meeting; counts people for space data. | Plain PIR alone will switch off on a quiet, seated room. Tune hold times to the way the room is used. | NCC Section J; AS/NZS 1680 (interior) |
Warehouse aisles | Microwave or mmWave, integrated per fitting | Picks up movement deep along racking; per-aisle 'follow-me' lighting so only occupied aisles are lit. | Standalone area sensors leave dead spots between racks; mount the sensor just above the highest stored goods. | NCC Section J |
Fire-isolated stairs & corridors | Integrated microwave (triggers before entry) | Senses approach through the door so the stair is lit before you step in; dims rather than fully switching off. | Full switch-off is not permitted — must dim to at least 30% after 15 min. Emergency function is separate. | NCC Spec 40; AS/NZS 2293 (emergency) |
car parks (Interior) | Microwave or ToF, integrated per light | Per-light detection covers blind spots a single area sensor misses; dim-to-standby between vehicles and people. | Avoid one timer-based area sensor for a whole deck; tune out passing traffic and weather movement. | NCC Section J; AS/NZS 1680 (interior) |
What this means in Australia
Most development in thermal and radar presence sensing has come from Europe and North America. In Australia, the implication is clear: NCC Section J already requires occupancy control in larger spaces, so sensors are now a compliance requirement rather than an optional upgrade.
Selecting the right sensor is usually a trade-off between cost and performance. In most environments, careful tuning is needed to avoid nuisance switching, and external lighting remains particularly challenging because range limits and fast-moving objects can reduce detection reliability.
In most projects, cost will still drive the decision. Even so, the next generation of sensors is expected to become more accessible over the next few years, giving users clearer performance benefits as these technologies enter the mainstream.
What to do about it
On your next fit out or retrofit, stop specifying 'occupancy sensor' as a generic line item. Match the sensor to how the space is actually used — still, seated work wants presence detection (thermal or radar), not movement detection (plain PIR); long racking and open decks want per-fitting integrated sensors, not one area unit; fire stairs want a sensor that triggers on approach and dims rather than switches off the light. Specifying the sensor type, not just 'a sensor', is what separates a system people leave switched on from one they rip out.
Sensor-type selection reference sheet
Six technologies you'll meet on a commercial job, side by side.
Sensor type | Detects | Sweet spot | Failure mode | Maturity |
PIR (passive infrared) | Heat of a moving body crossing its view | Enclosed offices, toilets, meeting rooms with line of sight | Misses still or head-on people; under-sensitive in warm backgrounds; degraded by dirt | Mature / low cost |
Microwave (high frequency) | Echo-time of a reflected signal; small movement, through thin walls | Warehouses, car parks, obstructed and open spaces | Over-triggers on any nearby movement unless carefully tuned | Mature / low cost |
Ultrasonic | Reflected sound waves; movement and some presence | Spaces with obstructions where line of sight is poor | Sensitive to air movement (HVAC); costlier than PIR | Mature / niche |
Thermal (low-res imaging) | Coarse heat image — shape, direction, count, stationary presence | Offices needing presence + people data; predictive maintenance | Higher cost today; resolution kept low by design | Emerging |
mmWave radar | Micro-movements down to breathing; true presence | Confirming a still person is present; any-light conditions | False triggers outside the zone unless tuned | Emerging |
ToF / IR array | Infrared pulse depth map; accurate people-counting | Counting and occupancy analytics (~0.4% error); privacy-safe | Can't always tell active vs passive desk use alone | Emerging |
NCC Section J sensor-compliance checklist
95% of the lighting load in spaces over 250 m² must be on a time switch or occupancy sensor.
Sensors must detect an occupant before they are 1 m into the space.
Lights must switch (or dim) off within 15 minutes of the space becoming vacant.
Choose a sensor that detects presence, not just motion, wherever people work seated or still — to avoid nuisance switch-offs that lead to controls being disabled.
Document the sensor type and settings so the as-built matches the Section J compliance pathway.
Warehouse and car park tuning guide
Use one integrated sensor per fitting rather than a single area sensor for the whole space — this removes the blind spots between racking and across a car-park deck.
Mount the aisle sensor roughly 0.45 m above the highest stored goods so racking doesn't block its view down the aisle.
Set unoccupied aisles to dim to a low standby level (around 10%) rather than fully off, so movement into an aisle brings light up instantly and safely.
Enable 'follow-me' control so light tracks a person or forklift along the aisle and the rest stays in standby.
In car parks, tune out passing traffic and weather-driven movement, and keep on standby light levels in unoccupied areas.
Fire-stair dimming compliance note
Fire-isolated stairs are the one space where you cannot simply switch lights off. Under NCC Specification 40, the lighting may dim to a reduced output (at least 30 per cent of peak) after about 15 minutes of vacancy, but full switch-off is not permitted, and the emergency lighting duty under AS/NZS 2293 — 90 minutes on mains failure, with scheduled testing — is a separate requirement that always applies.
The practical answer is an integrated microwave sensor that triggers on approach, so the stair is already lit as someone opens the door rather than after they've stepped into the dark. enLighten's emergency range has all have an integrated microwave sensors.
Future-proofing decision checklist
Specify the sensor type, not just 'an occupancy sensor', against how each space is actually used.
For seated or still work, choose presence detection (thermal or mmWave), not movement-only PIR.
For long racking and open decks, choose integrated per-fitting sensors over one area unit.
For fire stairs, choose approach-triggered detection that dims rather than switches off.
Where you want space-utilisation or people-count data as well as switching, weigh thermal or ToF — they deliver both from the same device.
Check the governing standard for the space, NCC Section J, NCC Spec 40, before locking the control strategy.
How enLighten can help
enLighten is an Australian designer, manufacturer and supplier of commercial LED luminaires and lighting controls, with more than 17 years specifying lighting for offices, warehouses, tunnels, car parks and public buildings. The problem this article describes — the wrong sensor in the wrong space — is one we solve at the design stage, by matching the sensor technology to the way each space is used and the standard that governs it, and by supplying the sensor and the fitting as a matched system rather than a sensor bolted onto someone else's luminaire.
Whether it's presence detection for offices, sensing across warehouse aisles, per-light control in a car park, or compliant dimming in a fire stair, we can specify the sensor type and the control strategy with you. The best time to bring us in is at the specification stage — before the sensor type is locked — so the system is one people leave switched on.