A vacancy sensor takes a manual-on switch and pairs it with automatic shut-off. You flip a switch or press a button to turn on the lights. Once no one’s there, the sensor shuts them off. This saves 20-30% more energy than regular occupancy sensors because you’re in control. If sunlight’s pouring in, you might skip turning on the lights. Occupancy sensors turn lights on whenever they detect motion, even if you don’t need them.
Modern buildings use vacancy sensors to cut lighting loads, up to 17% of a building’s energy, while keeping everyone safe and comfortable. The real difference between vacancy and occupancy sensors? You choose when the lights come on.
Occupancy sensors turn on lights any time they spot motion. After you leave, they wait and then switch off. Vacancy sensors are different. You push a button to turn the lights on, and the sensor handles turning them off after you’ve left.
This matters. When a conference room gets plenty of daylight, or someone just pops in for a file, vacancy sensors keep the lights off unless you turn them on. Occupancy sensors don’t wait - they flick the lights on, which can waste energy.
Vacancy sensors usually deliver even higher savings since you only flip the lights on when you really need them.
Use vacancy sensors in places like offices, conference rooms, or anywhere you get good daylight and a switch is close by. Skip them in stairwells, corridors, and warehouses - places with lots of entrances or where you can’t easily reach a switch. Don’t use them where lights need to come on right away for safety.
Manual-on control stops lights from coming on for no reason. If you just pop into a storage closet, walk through a sunlit office, or peek into an empty meeting room, you don’t need overhead lights at full brightness. Vacancy sensors let you decide.
Energy codes see the value. ASHRAE 90.1 and IECC require that lights can’t switch to full brightness automatically. You need manual-on control or partial-on, sensors can turn lights to 50% brightness when they catch movement. Full auto-on is only for public corridors, stairwells, restrooms, entrances, lobbies, or spots where safety demands it.
Today’s codes favor manual-on or partial-on control. If you use occupancy sensors, set them to 50% auto-on to meet code. Vacancy sensors meet “manual-on” requirements by default. California Title 24 requires vacancy sensors in offices of 250 sq ft or less, classrooms, conference rooms, and multipurpose rooms up to 1000 sq ft.
Vacancy and occupancy sensors detect motion or presence. The sensor keeps an eye on the coverage area, starts a timer when motion stops, and shuts off lights after the time runs out. You turn the lights on as you enter. Each sensing technology has strengths for detecting motion, stillness, and handling background noise.
Microwave sensors rely on Doppler radar at about 10.525 GHz to spot motion. Radar goes through walls and glass, so it can pick up unintended movement. Layout changes or environmental factors make calibration important.
These sensors are sensitive and can cover more ground, but tuning matters. You’ll find them in security jobs and specialized commercial uses. For typical lighting control, PIR or ultrasonic usually makes more sense.
Microphonic sensors use microphones to catch sounds from people. They use advanced filters to tell human sounds from background noise - HVAC, clocks, radios. You’ll always see microphonic paired with PIR in passive dual-technology sensors.
Sound detection helps in rooms with visual hurdles. It works best in quiet spots, since loud places can cause false triggers.
Camera-based sensors analyze video to check for people. They count, track, and can be very accurate in complex spaces. Privacy rules limit where you can use them - so you won’t find them in restrooms, locker rooms, or private offices.
Use video sensors only if you need visual confirmation and privacy rules allow. Most buildings avoid cameras and use tech like mmWave radar, or Wi-Fi/BLE sensors that give group counts, not personal info.
mmWave radar runs at 30-300 GHz, catching small moves like breathing and heartbeats. It spots people sitting still. Detection range reaches up to 10 meters for motion and 6 meters for micro-motion from a wall mount.
mmWave picks up presence, not just motion. This helps prevent lights from turning off while someone’s working quietly. Use mmWave in places where people are still for a while - libraries, study nooks, or quiet rooms.
mmWave works through non-metal materials and in any lighting. It costs more than PIR, but delivers better detection if stillness is common.
False-off is when lights go off while someone’s still there. False-on is when lights flip on with no one in the room. Both eat up energy and annoy people.
Placement is key. PIR might miss someone sitting still. Ultrasonic could mistake blowing curtains or airflow for activity. HVAC vents, heat changes, and vibrations all trigger false activations.
Choose spots where sensors cover the full space. Steer clear of indirect lights that make heat patterns. Run a quick audit now and then. Compare sensor counts with badge scans or room bookings to check accuracy.
Set up calibration every 6-12 months to keep sensors sharp. Adjust timeouts for each space. Five minutes is plenty for a closet. In a conference room, 15 minutes prevents lights from shutting off during quiet meetings.
Sensors must turn off lights within 20 minutes after everyone leaves. Most codes also favor manual-on or partial-on setups to cut wasted lighting.
ASHRAE 90.1 and IECC don’t allow lights to go to full brightness automatically. Use manual-on or partial-on at 50% brightness when someone enters. Full auto-on is only for public and safety-critical areas, like corridors, restrooms, entrances, and lobbies.
Vacancy sensors check all these boxes by default. You turn on the lights manually, they shut off automatically. If you go with occupancy sensors, configure them for 50% auto-on to stay compliant.
NFPA 101 applies for safety if you dim or use bi-level control in stairwells. Always meet their lighting minimums to stay safe while saving energy.
Automation systems use occupancy signals to control lighting, HVAC, and ventilation. A smart office shifts resources as people move - no wasted energy, no wasted dollars. Vacancy sensors send “occupied/unoccupied” signals so control systems can run smart schedules and patterns.
Lighting controls feed data to your building system. If a meeting room empties, the BAS raises the temp or dims the lights. Demand-control methods like this save up to $0.50/ft² a year on HVAC. Networked controls paired with occupancy sensors save as much as 30% in hybrid spaces.
BACnet is the standard link for lighting controls and building automation. Sensor data plugs straight into tools through BACnet or open APIs. Using open protocols lets you mix brands and skip vendor lock-in.
Vacancy sensors tell you if spaces are occupied or not, they don’t count people. For big-picture patterns, you need analytics tools that blend sensor signals with other data.
Dashboards combine these to show real-time use, dwell times, and traffic trends. Occuspace Micro sensors work in tight rooms; Macro sensors handle large zones. Both feed a single platform and API for easy insight on dashboards, apps, and system integrations.
Occuspace gives you a privacy-first occupancy platform that scales easily. Our Macro sensors scan Wi-Fi and Bluetooth activity in large zones. Micro sensors use mmWave radar for small rooms. Both send data to a single dashboard, API, and signage system. Get live stats, traffic trends, and dwell times across your portfolio - no cameras, no personal details, set up in days.
You need fast, accurate occupancy data that plugs right into your automation and analytics tools. Occuspace combines Wi-Fi/BLE scanning with mmWave for minute-by-minute metrics. Our platform supports BACnet, custom APIs, and exports. You can tie occupancy signals to HVAC setpoints, lighting schedules, and demand-control. We’ve helped clients save around $0.50/ft²/year on HVAC and cut custodial costs by 20-30%.
Look for simple installs, high accuracy, and privacy-first. Occuspace sensors go live in 1-2 days, no cabling. Our models deliver 95% accuracy with calibration and collect no personal info - just counts. Dashboards let you monitor in real time; APIs automate your tasks; signage helps with wayfinding. Our clients range from real estate and higher ed to healthcare and government.
Vacancy sensors drive energy savings and comfort by putting the switch in your hands. Manual-on control stops wasted lighting. Automatic shut-off keeps empty rooms from running up your bill. As energy codes favor manual-on and partial-on setups, vacancy sensors make compliance simple and effective.
Sensor tech keeps advancing. mmWave detection cuts false-offs. Dual-tech sensors reduce nuisance triggers. Open protocols like BACnet and modern APIs make integration smooth. You get smarter buildings that save energy, cut costs, and boost occupant experience.
Occuspace delivers privacy-first, easy-install occupancy intelligence for modern building automation. Sensors deliver real-time signals for your BAS, lighting, and analytics. You get what you need for demand-controlled ventilation, smarter cleaning, and right-sized real estate - all with no cameras or tracking. Ready to trim energy waste and use your space better? Occuspace is built for that.
