Viewpoint
Rob Owen, product specialist at Gewiss UK Limited discusses the importance of optical control of LEDs.
The prospect of LEDs becoming a serious alternative to HID lamps gained momentum in the early
noughties. Serious products were breaking through with dedicated white light, instead of a blend of RGB. The concept of using phosphor coating to manipulate the appearance of the visible light was nothing new, but the subsequent improvement in efficacy was the building block of the high power products we see on the market today.
With the advent of energy-saving compact fluorescent light bulbs for the home, the term ‘lumens’ has become more and more familiar to the entire market. The more lumens the better, and more lumens per watt is better still. However, the quality of an LED luminaire, or an LED installation, cannot be measured by the lumen package alone, or by a nominal payback period, or by the reduction in kW/hours. The key has always been, and will always be, to ensure the lighting task is adequately performed, with the right product, designed, specified
and installed correctly. It is entirely pointless to re-light a workshop, for example, with shiny new LED fittings that promise the earth and 100+ lumens per watt, if the LEDs are simply clustered in a little square with no optical control, and throw a
sledgehammer beam of light down onto a tiny area of floor. The uniformity will be poor, there will be ‘hotspots’ of light under each fitting, and the glare will be unbearable. This is not a like-for-like replacement, regardless of what the manufacturer may claim, and so the reduction in energy is a bit of a cheat. Okay, fewer watts are being consumed, but this should not be at the expense of the lighting task.
Optical control of LEDs is essential to ensure efficient, comfortable and effective products and schemes. Too many products on the market right now are just
conventional light fittings
with LEDs shoe-horned in, rather than being properly designed and optimised from the ground up. This applies to indoor lighting, commercial, industrial, street lighting, floodlighting; every LED luminaire that has to perform a task should be scrutinised and tested to ensure it is up to the job. If so, then the energy savings can be sensibly evaluated.
We are of course living in a terribly price-driven market, which unfortunately has a tendency to push quality down as manufacturers clamour to minimise costs. Warranties which stretch longer than a lot of the ‘manufacturers’ have been in business themselves do little to provide reassurance, and it will be interesting in a few years time to see exactly what will happen to all these cheap products if they begin to fail, as to whether the promised ‘return on investment’ for the end user
is actually borne out. Contact
GEWISS UK LIMITED T: +44 (0) 1954 712757 W:
www.gewiss.co.uk
82
www.a1lightingmagazine.com
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