Use automatic lighting controls with motion sensors, time control, and dimmable lights

Process area: Lighting
Payback: 6-12 months payback
Complexity: 3/5
Adoption: 60%
Avg. save: €4,000-14,000
CAPEX: No

Action overview

Lighting controls can help reduce energy use from 20% to 70%. These can be combined with daylight or natural light sensors to supplement electrical lighting fixtures, or turn off lights when they are not in use or dim them on demand with electronic ballasts (e.g. T5). These controls offer a low-cost way to significantly improve lux levels and reduce lighting costs. Ensure occupancy patterns match timing controls and adjust timing controls to match occupancy patterns and maximize lighting efficiency.

Tips & advice

1. Evaluate the different "zones" currently used for your light switches. Zoning switches ensure that lights for one area don't turn off lights in other zones irrespective of occupancy. Examples of different zones in your office can be: Owned (private office), Shared (Open Plan office, production areas), Temporarily owned (meeting rooms, classrooms), Occasionally visited (storeroom, toilet), Un-owned (Corridors, stairs), Managed (Reception, exhibition areas).
2. Before installing any automatic controls or dimmers, remember to investigate occupancy patterns with questions such as: Who is using the space, what are they doing, when will they be there, how long will they be there?
3. Install the following sensors/controllers as appropriate and conduct a post-installation occupancy audit to ensure they are working as desired. Also evaluated the pre- and post-installation energy use.
4. Light Sensors: In rooms where daylight is coming in from one direction, consider using various circuits to increase light intensity as you move away from the window. Outward facing sensors are generally used only for switching lights on/off. Expect to use sensors inside the premises and in the different zones for dimming functions.
5. Motion sensors: evaluate who is using that space, for what purpose, what time and how long they will be there. Based on their occupancy pattern dim or turn off lights when the room is vacant. For example, for someone that is in and out of an area frequently (every 5 minutes) dimming lights in under 2 minutes is not a good idea.
6. Remote monitoring can be useful to adjust settings of your fixtures and control lighting without significant labor costs.
7. Time control: Focus on exterior lights initially and take into account changing daylight during the seasons and daylight-saving times (if applicable). It is likely that indoor systems will need local overrides to make this successful.

Additional considerations

The costs vs. savings will depend on how sensors are fitted and how the wiring is arranged. For example, you could have an office with windows on one side with a bank of parallel fittings, a photocell, and dimmers to adjust for natural light levels.

Often, automatic timing controls, although installed, do not match occupancy patterns. This results in situations where lights are kept on in rooms or areas that are unoccupied. This happens when the duration of the timer is set much longer than required. Each time an occupancy is detected the timer is reset, even in cases when the occupancy lasts for a few seconds or minutes. Another adverse case is lights going off too frequently. Therefore, occupancy pattern sensors should be fine-tuned through a trial-and-error process that incorporates feedback from employees and takes into account lighting energy consumption trends. Allow employees to adjust these controls through a fast process controlled by dedicated lighting representatives.

Remember that employment costs are higher than electricity! Lighting changes should not affect the staff's health and well-being in the workplace.

List of manufacturers: Green Ballast, Easylite, Encelium Technologies, Hunt Dimming, Ledalite Architectural Products, Leviton, Lutron, Noresco, PLC-Multipoint, Watt Stopper.