Why LEDs are not our lighting saviour 07.01.20

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Lighting in Singapore by Timo Wagner

The design possibilities are endless and the sustainability credentials impeccable, but they give our homes as much warmth as a hospital ward, argues Max Fraser

Now bear with me. I’m fully aware that over the last decade, LEDs have been held up as our saviour. There’s no denying that this digital device consumes considerably less energy than the incandescent light bulbs that they’ve superseded by law. They’re sold to us as lasting for up to 50,000 hours and their tiny size and very low heat output has allowed designers to create a whole new typology of thin and flexible lighting.

So why do I refuse to go near them in my own home? There is a basket of instantly rejected LED bulbs that sits neglected in my basement. I tried several times; heading for a different brand, buying the bulb that says ‘equivalent to 60w’ and then getting it home and having an instant reaction against its harsh tone and shadow quality. On the rare occasion I pass an electrical shop selling ‘the last remaining stock of incandescent light bulbs’, I buy as many as I can carry.

The aesthetic assault caused by so many LEDs is the warmth, or lack of it. Look closely on the box and you might find a four-digit number followed by K. Forgive me if I have no idea what this means. 2700K is apparently warm light and 3000K is white light. 4000K is DON’T LOOK AT ME light. 5000K is KILL ME light and might usually be found in clinical environments. Add to this the shadows; I find it hard to describe the bleakness of the shadows.

But there is a much less understood side to LEDs that needs our attention: blue light hazard. Blue light is a big player in natural daylight and acts like caffeine for our bodies. Late-night LED glow from our devices is a major cause of sleep deprivation as it inhibits the production of our sleep hormone, melatonin. The same goes for our lighting, which is why you should have warm LED lighting (2700K and below) at home, especially in your bedroom.

In the workplace, the daytime alertness achieved from the blue light of LEDs hopefully aids productivity. But what about the flicker and its effect on our health? Linked to every LED light source is a driver that converts AC mains power supply to DC for the LEDs to function. The electrical waveform switches rapidly between on and off states, but the disparity between AC and DC waveforms creates a flicker which is not immediately perceptible to the human eye. This rapid pulsing has been associated with eye strain, fatigue, headaches and even seizures, and is smoothed out only by additional capacitors in good quality drivers.

I know the technology is always advancing, but until I’m well versed in the spectral content and flicker metrics of LEDs, I will minimise exposing myself to them, let alone children or staff.

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