A few years ago I performed an energy audit for an office building and developed a good half-dozen sound energy strategies to save them money. While discussing occupancy sensors with the building’s owner, he understood its value. I offered to help, but he turned me down. He was going to go to the nearest Home Depot to pick up some on sale and install them himself. Well, big mistake. I suppose this owner so understood the simplicity of how an occupancy sensor works that he felt that no thinking was necessary. On the contrary, proper planning will make the difference between a reliable, cost-saving venture vs. an unsuccessful one. A few things to consider:
1. Invest time, determine where sensors can save the most by observation. Determine which areas have long periods of dormancy and can use occupancy sensors to save energy and which areas are regularly used. Yes, one can guess the need for occupancy sensors by evaluating a room’s use (for example, an IT room, where, theoretically, people enter rarely). One can review conference room reservation logs, but in many cases, rooms are fully booked, but hardly actually used. Thus, spend a few days to observe which rooms are actually unoccupied for long periods. Perhaps there is significant flow in and out of the IT room after all; perhaps a conference room really is or is not used as much as the logs show.
2. Accurate, up-to-date floor plans. Once areas are identified, plans are needed to determine which lights and electrical panels serve each space to place the sensors appropriately. With this information you can determine in which rooms to place occupancy sensors (connected to which panels) to get the best effect.
3. Placement of sensors. This is crucial to their effectiveness and occupant satisfaction. Sensors should be capable of “seeing” anyone who comes in the door. In some cases, multiple sensors may be needed for odd-shaped rooms or for spaces shielded by high cubicle walls or cabinets. Do you place the sensor high up on a wall “to see” more of an area, but make it inconvenient to repair? Or closer to where people work?
4. Pick your occupancy sensor brand carefully. Don’t buy them just because they are cheaper or are on sale. There are differences in quality and sensitivity. Installing the “wrong” sensors can affect morale and efficiency. If your budget allows, consider dual technology sensors, those that sense both motion and thermal, particularly for large or odd-shaped spaces. You don’t want lights going out just because people in a room have not moved in some time. This just happened to me. The host was quite embarrassed.
5. Provide early notification to staff. Establish an installation schedule and give advance notice to staff approximately when occupancy sensor installation will occur in their areas. Send staff either a brochure or some summary of the specs. of the sensors, so they have an idea of what it can and will do.
Final question: does one still procure occupancy sensors if one has switched to LEDs? Installing LEDs and saving energy costs should not preclude one from installing occupancy sensors. Even reduced wattage lamps, such as LEDs, represent wasted electricity and cost if on for many hours when a space is unused. The math may be different (lower savings because the cost of wasted electricity is lower), but in most cases there should be a reasonable, if somewhat longer payback for using occupancy sensors.
CCES has the experts to help you perform a full assessment of your lighting and total energy usage and needs, and provide detailed smart strategies to reduce usage, demand, and cost that have worked for others. Contact us today at 914-584-6720 or at karell@CCESworld.com.