Fluorescent lighting is by far the most commonly used lighting in commercial and institutional settings but there are many other types including:
High-Intensity Discharge (HID)- An HID lamp produces light by means of an electric arc between tungsten electrodes housed inside a translucent or transparent quartz tube. Depending on the type of HID lamp, the tube is filled with different gas and metal salts, which produce varying levels and qualities of lighting. Compared with fluorescent and incandescent lamps, HID lamps have higher luminous efficacy meaning they provide a greater amount of light output per watt of electricity input. Like fluorescent lamps, HIDs require ballasts but can also take up to ten minutes to produce light when first turned on. Since the lamps take awhile to establish, they are most suitable for applications where they stay on for long periods and are commonly used for outdoor lighting and in large indoor arenas. The most common types of HID lamps are:
Mercury Vapor, Metal Halide, High-Pressure Sodium and Low-Pressure Sodium. Furthermore, with rapid advances in fluorescent lighting technology, many commercial and institutional locations are replacing HID systems with high output fluorescents ? typically using T5 lamps with special ballasts ? to provide higher lighting efficiencies.
Incandescent ? Incandescent lighting is the most common type of lighting used in residential settings but they are also found in businesses for portable lighting, such as table lamps or for decorative purposes. Incandescent lamps light up instantly, providing a warm light and excellent color rendition and operate without a ballast. Incandescent lamps, however, have a low efficacy compared to other lighting options (10?17 lumens per watt) and a short average operating life (750?2500 hours). They are the least expensive to buy, but because of their relative inefficiency and short life spans, are usually more expensive to operate.
Light Emitting Diode (LED) ? an LED light is a semiconductor light source, which was first used as indicator lamps in many devices but are increasingly used for general lighting purposes. Introduced as a practical electronic component in circuit designs early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet and infrared wavelengths, with very high brightness. LEDs present many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved robustness, smaller size, faster switching, and greater durability and reliability. However, they are relatively expensive and require more precise current and heat management than traditional light sources. Current LED products for general lighting are more expensive to buy than fluorescent lamp sources of comparable output.
Tubular Fluorescent Fixtures ? Fluorescent tube lamps are widely used in commercial and institutional environments as they are more energy efficient than incandescent and produce better ambient light without the glare. The most commonly employed tube-type fluorescent fixtures use 4? T12 lamps – 12/8 or 1 ? inch tube diameter ? which are installed in groups of four in a dedicated fixture with a ballast required for operation. With technical advances in fluorescent lighting, the new generation of smaller diameter lamps (T-8 and T-5) is particularly efficient due to improvements in lamp design and significant changes to how the ballast operates. It is important to understand that lamps and ballasts work as a system and the overall efficiency and lighting capability of a fixture is dependent on the lamp/ballast combination. Fluorescent lamps can last up to 20,000 hours of use and have wide-spread applications. Currently, a common but effective lighting upgrade is to replace four T12 lamps with two T8s affixed with a reflector. This change can provide up to a 60 percent savings in electricity while maintaining required lighting levels.
Compact Fluorescent Lamp (CFL) ? CFLs combine the energy efficiency of fluorescent lighting with the convenience and popularity of incandescent fixtures. CFLs can replace incandescent lamps that are roughly 3-4 times their wattage and provide savings of up to 75% of the initial lighting energy. Although CFLs cost 3 to 10 times more than comparable incandescent bulbs, they last 6 to 15 times as long (6,000?15,000 hours). As CFLs are like standard fluorescent lamps, they consist of two parts: a gas-filled tube, and a ballast for operation. They are available in a variety of styles, shapes and performance characteristics and are a very cost effective and simple replacement for incandescent lamps in ceiling, table, and free standing fixtures.
Tungsten-Halogen ? Tungsten-Halogen lamps, a type of incandescent lighting, achieve better energy efficiency than standard, incandescent A-type light bulbs, due to their construction make-up of a gas filling and an inner coating that reflects heat. These lamps provide excellent color rendition but are considerably more expensive to buy than standard incandescent lamps but in the long run are less expensive to operate because of their higher efficacy.
Induction Lamps ? In contrast with typical electrical lamps that use electrical connections through the lamp envelope to transfer power to the lamp, in electrode-less lamps the power needed to generate light is transferred from the outside of the lamp envelope by means of (electro)magnetic fields. There are three advantages of eliminating electrodes: extended lamp life, because the electrodes are usually the limiting factor in lamp life; the ability to use high efficiency light-generating substances that would react with metal electrodes in normal lamps; and, improved collection efficiency because the source can be made very small without shortening life – a problem in electrode based lamps. Practically speaking, induction lights require far less maintenance due to their long life spans (up to 100,000 hours).
