In many cases, light changing maintenance programs and procedures can result in substantial savings. Simple techniques such as regularly cleaning fixtures, lamps and lenses; following relamping schedules; cleaning surfaces in the space; and other techniques improve the quantity and quality of light created by the existing system and can produce both cost and energy savings. Dust, grease, and other dirt accumulations on lamps, lenses, globes, and reflecting surfaces of the fixture can reduce light output by as much as 30 percent. Lighting professionals recommend that fixtures be cleaned every two or three years. In greasy, dusty, or smoky settings, or when light fixtures are integrated with the HVAC system, cleaning may need to be more frequent.
Check to see how clean the lamps and fixtures are, and do any necessary cleaning before deciding on efficiency changes in the lighting. Cleaning will increase the light output and may allow you to remove some lamps or to install lower wattage ones. To maintain your lighting efficiency gains, cleaning is particularly important. If you have reduced light levels in previously overlighted areas, timely cleaning will assure you of continuing to have enough light for the needs of each area.
As fluorescent lamps age, their light output decreases, yet they consume the same amount of energy producing this lower light level. Timely replacement of old lamps eliminates this inefficiency. A practice that is becoming common in facilities with a large number of ceiling lights is group relamping, or replacing all lamps in an area near the end of their useful life. Group relamping can cut replacement labor costs in half when efficiently done by a team going from fixture to fixture, and it can assure proper light levels, because fluorescents dim as they age. It also helps prevent unwanted interruptions in work or some other activity when individual lamps burn out at random.