Lighting is important for most non-domestic applications, and is often kept on during daylight hours of occupation. For this reason (and for lower maintenance costs), high efficiency lights are vital; consider using high reflectivity luminaires, T5 tubes, LED lights and concentrated fluorescent spot lights, as well as the more commonly seen compact fluorescent lights (CFLs). Motion sensors that switch off lights in unoccupied areas can also lead to substantial savings. Try to avoid using low voltage halogen lights in display units; they are quite inefficient and generate a lot of surplus heat that may be difficult to lose.
External lighting – including security lighting – can also add a surprising amount to your organisation’s carbon footprint. Make sure mercury discharge or tungsten filament external lights are replaced by lower energy metal halide (SON) or multiple fluorescent lights. And consider whether all lights need to be left on all night for security purposes in areas such as car parks – concentrate on lights in areas at risk from vandalism or illuminating areas observed by security cameras.