Given the rapid advancements in lighting technology, and the availability of a wide range of lamps in the market, selecting the best lamp option for any application can be a confusing process.
When purchasing lamps for any application, it is important to know and understand their advantages and disadvantages.
Metal halide lamps
Metal halide lamps produce light when an electric arc is passed through a gaseous mixture of vaporised mercury and metal halides. A member of the high intensity discharge (HID) lamp family, metal halide lamps produce a whiter light, are more energy efficient than halogen lamps, and ideal for indoor, high ceiling and outdoor applications.
Disadvantages of metal halide lamps include high cost and harmful content. Additionally, these lamps operate at high pressures and temperatures, and require a warm-up period before reaching full light output.
Also known as tungsten halogen lamps or quartz iodine lamps, halogen lamps are an advanced form of the incandescent lamp containing a small amount of a halogen such as iodine or bromine. The halogen gas and the tungsten filament combine to produce a halogen cycle chemical reaction, which re-deposits evaporated tungsten back onto the filament, increasing its life and maintaining the clarity of the envelope. A halogen lamp can therefore, be operated at a higher temperature than a standard gas-filled lamp of similar power and operating life, producing light of a higher luminous efficacy and colour temperature.
Advantages of halogen lamps include small and lightweight design, longer lifespan than incandescent lamps, no mercury content, high light output, and instant start up without any warm-up period required.
Disadvantages include high temperature operation that can be very hot to touch, energy efficiency lower than metal halide lamps, and potential for malfunction if touched.
Compact fluorescent lamps (CFLs)
Compact fluorescents lamps, also known as CFLs use gas, mercury particles and phosphor to create light. Electricity excites the gas, which when combined with mercury particles, produces invisible ultraviolet light. The UV light then hits the white phosphor coating inside the bulb, causing it to fluoresce and emit white light. Circuitry inside the base of the light prevents flickering.
Advantages of CFLs include choice of various colour temperatures, average lifespan of 10,000 hours, consumption of approximately 80% less energy, and flexibility to fit into most existing light sockets.
Disadvantages include mercury content, lower lifespan from constant switching on and off, and UV ray emission.
Light emitting diodes (LEDs)
Light emitting diodes, also known as LEDs are electrical components with two terminals, which conduct electricity only in one direction. With an electrical current, the diode emits a bright light around the small bulb. Connecting a diode to an electrical current excites the electrons within the diode, making them release photons, which is seen as light. The colour of the light is a direct result of the energy gap in the semiconductor of the diode. LEDs therefore, can produce a spectrum of colours easily and brightly, while using very little electricity to do so.
Advantages of LED lamps include high energy efficiency, shockproof and durable design, 35,000 – 50,000 hours lifespan, wide variety of beam angles to suit different applications, no UV ray emission, no harmful content, choice of interior and exterior fittings, reduced maintenance and electricity costs, instant start-up with no warm-up period required, unaffected by cold weather, and environmentally friendly.
LED lamps can however be expensive to purchase.
Each type of lamp described here has its pros and cons but the advancements made by LED lighting technology will allow LED lamps to replace most forms of lighting in the near future. Current replacements include high bays, downlights, T-bar troffers, tubes, panel lights, shoplighters, wall lights, garden uplights, floodlights, canopy lights and a wide variety of lamps.
ANL Lighting is a leading distributor of commercial light fittings, lamps, electronic transformers, bollards, LED lighting and downlights.
Written by Amber Miles