According to the Energy Star Building Manual, lighting consumes nearly 35 percent of the electricity used in commercial buildings in the U.S. In 2010 California commercial and industrial businesses spent approximately $7.45 billion for lighting alone 1.
Lighting systems also affect other building systems through the waste heat they produce. Adding controls and sensors to existing lighting systems, de-lamping in over-lit areas and replacing less efficient lamps with new high efficiency lamps will reduce the lighting system energy use; the efficiency of HVAC systems will be increased; and the visual environment will improve 2.
Follow these guidelines to ensure that the upgraded system is effective and efficient:
Daylighting – The sun is the most efficient source of light. By using daylight to supplement electric lighting systems owners can cut energy use, reduce peak demand, and create a more desirable indoor environment. Use conventional glazing, light shelves, skylights and clerestory windows to bring light into a building. The glare resulting from daylight can be minimized by using translucent materials and bouncing the light off surfaces. Automatic lighting controls complete the daylighting plan by sensing ambient daylight and reducing electric lighting. Without these controls no energy will be saved.
Linear Fluorescent lighting systems are the most common lighting systems in commercial and industrial spaces. They offer high efficacy, long life, and good light quality in areas with low to medium ceiling heights. For the typical lighting upgrade project the best choice is the high performance T8 (eight eights inch diameter) aka “super T8s” which can be used to replace T12s and standard T8s. Since they are four or eight feet in length the lamps can be replaced without replacing the fixtures. However, to maximize the high performance T8 lamps high-performance ballasts should also be installed.
T5s (5/8” diameter) are only available in metric lengths. Therefore, they are typically not a good option in retrofits.
High intensity fluorescent lamps are ideal for areas with ceiling more 15 feet high.
Compact Fluorescent Lamps – CFLs are used primarily as replacements for incandescent lamps in down-lights, sconces, table lamps, task lights and wall washers. Costing more than a standard incandescent bulb, they quickly pay for themselves in energy savings. CFLs come in two forms, pin-base and self-ballasted (screw-base).
High Intensity Discharge Lamps – HIDs are primarily used in outdoor lighting, retail, and remote-source lighting. HID lamp types include mercury vapor (old inefficient technology), metal halide and sodium.
Light Emitting Diodes – LEDs are solid-state electronic devices that emit light in a specific direction, reducing the need for reflectors and diffusers that can trap light. They have a long life and are vibration resistant. Traffic signals, exit signs, retail accent lighting, and large outdoor displays are some of the areas that lend themselves to LED lighting.
Automatically Controlled Lighting – The simplest way to reduce lighting cost is to turn off the lights when they are not needed. Energy management systems (EMS), occupancy sensors, photocells, timed switches, and dimmers can provide tremendous energy savings and should be an integral part in any lighting retrofit project.