Text: Prof. Susanne Brenninkmeijer
Photo: Wikipedia

05. Mar 2013

LED – the answer to everything?
Some critical observations

Since their invention white LEDs have developed rapidly in leaps and bounds. Efficiency is improving fast and every month we are witness to new developments and technologies. At the world’s biggest light fairs in 2012, 90 per cent of the light sources used were LEDs and the majority of luminaire manufacturers only displayed their latest LED-adapted products. This state of affairs is more confusing than it is inspiring.

The time has come to verify the facts. We need to include social factors when we start the discussion on the real status quo of the market – designers need to understand what responsibility they bear towards the environment and the users of the spaces they design the lighting for. Let’s forget the hype and focus our attention on reality!

Information published a couple of years ago on the potential serious health hazards caused by LED lighting, in particular in the case of children, gave rise to voiced concern – at least throughout Europe – which was soon swept away again by a further wave of enthusiasm, a wave of apparent advantages of light-emitting semiconductors, augmented by general despair at the phase-out of the incandescent lamp that left no real alternatives. Top of the list is energy efficiency, the prime reason quoted for phasing out the incandescent lamp, and in 90 per cent of all cases the reason for changing to LEDs. But to what extent do LEDs fulfil the promises made by the manufacturers when it comes to efficiency rates of up to 120lm/W and a service life of 50 000 hours?

Expectations as to energy saving as a consequence of switching from incandescent lamps to compact fluoresecent lamps were initially met with bitter disappointment.

The term “energy-saving” would appear to relate more to the concerns we should have regarding production and disposal costs for such lamps and the inherent problems arising from those processes. The question that springs to mind is whether the prognoses for efficient light-emitting diodes are not based on similar calculations. In November 2011, the German magazine “Öko-Test” published the results of tests on eleven LED retrofit lamps available on the market as replacements for a 60 watt incandescent lamp. The German construction biologist Wolfgang Maes discovered that of the eleven LED sources tested only three fulfilled the efficiency specifications quoted. Seven of the test sources did not produce the lumen output quoted on the packaging, and one did not even produce 16 per cent of the quoted amount. Two specimens failed to meet the rated service life of 50 000 hours by 47 000 hours (!), which is ridiculous to say the least. This all results in frustrated end-users, who feel they have wasted their money, and – in the design field – to frustrated clients, who feel cheated at having their expectations raised by exquisitely worded advertising slogans and a list of advantages as long as your arm from the lighting industry, and thwarted as soon as the light sources are put to real use. It’s about time we all got more realistic. […]

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The full version of the article can be found in PLD No. 86.

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