Why controls pay off
An LED fixture uses far less power than older lighting, but it still uses power every hour it is on. Controls cut the hours. In storage rooms, washrooms, meeting rooms and warehouse aisles, lights are often on far longer than anyone is there.
- Occupancy and vacancy sensors respond to people.
- Daylight sensors dim fixtures when daylight is enough.
- Timers and astronomical clocks follow a schedule or sunrise and sunset.
- Networked controls tie fixtures, sensors and schedules together for a whole building.
At home, the gains are smaller but the convenience is real: garage lights that turn off by themselves, closet lights, and stair lights you never have to fumble for.
Occupancy or vacancy?
An occupancy sensor turns lights on when someone enters and off after the room is empty. A vacancy sensor requires you to press the switch to turn lights on, then turns them off automatically.
Vacancy mode saves more in rooms with windows, since people often do not need the lights at all. Occupancy mode suits washrooms, storage, stairs and garages, where hands are full or walking in the dark is unsafe. In commercial buildings, the energy code adopted in Alberta may specify which type is needed in certain spaces for new construction and some renovations.
Sensor technologies
| Technology | Detects | Good for | Watch out for |
|---|---|---|---|
| Passive infrared (PIR) | Heat moving across zones | Small rooms, hallways, garages | Misses small movements and anything out of sight |
| Ultrasonic | Changes in reflected sound | Washrooms with stalls, offices with partitions | Air movement can cause false triggers |
| Dual technology | Both, with settings to require one or both | Open offices, classrooms, meeting rooms | Higher cost, needs proper setup |
| Microwave | Motion through some materials | High bays, outdoor, large open areas | Can see through walls if over-sensitive |
Placement makes or breaks a sensor
Most sensor complaints come from placement, not from the product. Lights that switch off on someone working quietly at a desk, or turn on whenever someone walks down the hall, are usually a mounting problem.
- Make sure the sensor can see the person at their usual spot, not just the doorway.
- Keep sensors away from supply air diffusers and heaters.
- Avoid aiming through doorways or glass toward a corridor.
- Set a time delay long enough for quiet desk work. Too short annoys people; too long wastes energy.
Daylight, schedules and networks
Daylight sensors work best in zones beside windows and under skylights, dimming fixtures smoothly rather than switching them. Edmonton's daylight varies hugely through the year, so a properly set daylight zone pays off in summer and steps back in winter.
Astronomical time clocks calculate sunrise and sunset for our latitude, which makes them ideal for exterior and parking lot lighting. See parking lot and site lighting.
Networked lighting controls connect every fixture to a system that can be scheduled, reported and adjusted from a computer. They suit larger buildings and pair well with an LED retrofit. For office layouts, see office lighting design.
Setup, homes and next steps
Sensors need setting up after installation: time delay, sensitivity, daylight level and which technology triggers the lights. Ask for this step, often called commissioning, in your quote. A system that is not set up properly gets disabled with tape by frustrated staff.
At home, many smart switches and sensors need a neutral wire in the switch box. Older Edmonton homes often do not have one there. An electrician can check before you buy and recommend a product that suits your wiring.
Installing a sensor switch means working in a box with line-voltage wiring. Have a licensed electrician do it, especially in older homes with aluminium or ungrounded wiring.
We design and install controls as part of office lighting upgrades and energy audits that show where they will pay off.
Common questions
What is the difference between an occupancy and a vacancy sensor?
An occupancy sensor turns lights on and off automatically. A vacancy sensor needs you to turn the lights on, then turns them off when the room is empty.
Why do my sensor lights turn off while I am still in the room?
Usually the sensor cannot see you, the time delay is too short, or a PIR sensor is missing small movements. Repositioning, a longer delay or a dual-technology sensor usually solves it.
Do lighting sensors work with LED fixtures?
Yes. LEDs switch on instantly and handle frequent switching well, which makes them a better match for sensors than older lamp types.
Are lighting controls required in commercial buildings?
For new construction and some renovations, the energy code adopted in Alberta can require certain controls. Your designer or permit authority will confirm what applies.
Codes and permit rules change and every building is different. For work on your system, talk to a licensed electrician and your local permit authority.