Light Emitting Diodes

Brief description

Light emitting diodes convert electricity to light in a tiny chip that's enclosed in clear plastic. Being 5 times more energy efficient than standard incandescent light bulbs, they are very cheap to run. The flip side to this is the fact they are very expensive to buy. Although LED designs vary, each LED produces relatively little light compared to traditional incandescent light bulbs and halogens – though this is improving all the time. Lamps are produced by combining many LEDs into round shapes or strips.

LEDs have the potential to be extremely efficient and good quality ones have a life in excess of 30,000 hours. The technology comes in many forms such as lamps to replace the much less efficient incandescent light sources or incorporated into light fittings for a wide range of applications. The technology is developing rapidly and new products are coming onto the market continuously. Some caution is necessary when considering using LEDs. The quality of the products available varies considerably from the very good to some that fail to deliver the stated light output and may reach the end of life in a relatively short time. It is difficult for most people to know which is the good product and it is recommended that LEDs are purchased from specialist lighting stores where guidance can be obtained. It can pay to consider established brands that are known and trusted. LEDs with a warm (3000 Kelvin) colour appearance are recommended for domestic lighting applications. Questions to ask when considering LED lighting:

• Will the LED go into a closed or recessed fitting? LEDs don’t like heat so if they are recessed into a ceiling ensure they either have a way to remove the heat or are well ventilated. The greater the heat, the shorter the life of the LED.
• What is the light colour? Like CFL lamps, LEDs can come in a range of colours. If you want the same light colour as your standard incandescent light bulb, choose warm white (2700K – 3000K).
• How long is the warranty? You will hear claims of LED lamps lasting up to 100,000 hours, however, no manufacturers will support them for that lifetime. If a manufacturer claims anywhere between 20,000 and 60,000 hours lamp life that is more realistic. And you would expect a warranty of 5 years minimum.

Advantages

Good quality light emitting diode lamps can be extremely efficient and cost little to run. They can also have a long life, often conservatively estimated to be 30,000 hours plus. LED produce a high level of brightness and intensity so are very good for paths and other applications where you want to see where you are going. From a household perspective LEDs are a fit-and-forget proposition – good for difficult to access locations, for decorative lighting and for areas where low level of lighting is required for long periods of time – such as down stairs or along a hallway where night lighting is needed to allow children to find the bathroom in the night. They can also be used in lamp shades and other applications where it is replacing lamps up to a maximum of 50W.

Disadvantages.

LEDs have yet to product the light output of the most common 100W, 75W and 60W bulbs. LEDs are also expensive to buy compared with other lighting options. There are large variances in quality and performance. If you can buy an LED very cheaply (less than $30 standard retail) then there is a high likelihood the light output will be low and it will not last the stated lifetime.

Ongoing development.

No other technology has the potential to revolutionise home lighting in quite the same way as LEDs. Think continuous strip lighting, light panels and other innovative products that last for many years. LEDs are quickly finding their way into street light solutions so it is only a matter of time before we are all using them day-to-day.