LED lighting has been evolving rapidly over the last few years. With increasing pressure to reduce energy consumption and costs, LED lighting has been the subject of much debate and hope. Consuming much less energy than other lighting types, being low voltage and cool to touch are some of their many advantages.
LED lamps have been around for many years. The two main challenges however have been light output and heat. Whilst LEDs run cooler than traditional incandescent lights, the heat they do produce can reduce their life. Many of the higher output versions typically have large aluminium heat-sinks on the back in order to effectively dissipate the heat generated.
So what is so special about LEDs? Why all the fuss?
There are many factors involved with LED lighting including electrical and optical constraints - whilst they are an impressive solution it is one that is still evolving.
Lets start by narrowing down some of the issues. firstly, most people are looking for LEDs as a replacement for traditional downlights. It is this particular role that has been the most challenging for many reasons:
- Physical size - As mentioned earlier, good high-power LEDs tend to have large heat-sinks on the back. With many downlight fittings having rigid backs, the LEDs simply will not fit in. There are many options which do work and indeed dedicated LED fittings but the available range is still relatively small compared to the existing halogen downlight market
- Colour - Most traditional halogen lamps sold have a warm colour temperature (around 4000k). Whilst there are warmer and cooler alternatives many of the people we have worked with are looking for that warmth of colour. LEDs are traditionally a cold light (5000-6000k); warmer variants are based around the introduction of amber LEDs or filters into the lamp in order give the effect of warmth. Its not a perfect replica but successive generations are improving rapidly.
- Light output - Traditionally LEDs have been used as indicator lamps in everything from cars to washing machines and clock displays. Their basic design was never for high light output though until now - managing the heat constraints and preserving or improving upon the efficiency have added tough constraints to the design. The result is that on a single lamp for lamp basis, LEDs have a much lower light output than halogen equivalents. The more powerful LED lamps use multiple LEDs in a cluster formation to achieve the required output. In order to achieve the various perceived colour temperatures LEDs use filters or other similar techniques within the LED itself. The net result of this is a further reduction in light output. There are now LED lamps which have over 600lm/W output - a real threshold for general acceptance.
- Light cone - Building upon the previous point, LEDs have a very directional light output. That is to say that the cone of light emitted is very narrow compared to a typical halogen. Optical lenses are used on LED lamps to create a wider cone however the net light output obviously decreases over a wider area which must be taken into account.
- Dimming - Dimming LEDs is possible but requires more planning than the dimming used for traditional lamps. There are a number of reasons for this. Firstly, most of the transformers available only support specialist dimming methods (0-10v or DMX typically). This requires additional parts or systems to achieve. There are "normal" equivalents becoming available however care must be taken to meet the minimum wattage requirements of most dimmers as the very nature of LEDs using less energy means you may breach this threshold and the dimmer may not work or break!
- Wiring - The wiring for LEDs may also be different for many LEDs. 0-10v or DMX dimming will require extra cables, depending on the number of transformers and type the connections may be in series as opposed to parallel wiring usually expected.
- Cost - Put plainly, LEDs cost a lot more than traditional lamps to buy and install. The costs are not that straightforward however as a single LED lamp may use up to one fifth of the energy of a halogen downlight and can last up to ten years.
We have looked in detail at downlights but the world of LED lighting is very much more diverse. Whilst many of the same criteria apply, they are often less important where LEDs are used to provide colour, entertainment or lighting up swimming pools and building façades. The applications and products are endless.
We have worked extensively with LEDs in all their forms in a number of scenarios and can design and install solutions to suit from small rooms to entire buildings.