When you run electric current through a tungsten filament in an incandescent light-bulb, you waste roughly nine times the energy transformed into light, as heat. And those old incandescent light-bulbs always need changing: each one lasts around three months at average usage.
By comparison, when you switch on a Compact Fluorescent Light (‘CFL’), it uses roughly one fifth of the energy of an incandescent of similar brightness, and will typically last two and half years.
But better still, light emitting diodes (‘LEDs’) waste virtually no energy as heat, and last approximately thirteen years at average usage. A genuine step-change in efficiency, but there is much more to LEDs than just saving money and resources.
Lights of different wavelengths create different effects on the people and things they shine on. Some of these differences we are not conscious of; those which we can see are described as ‘colour temperature’ and measure in units called Kelvins (‘K’). LEDs have a natural flexibility which not only means that they are capable of a wider range of wavelength and colour temperature, but even that individual LEDs can themselves change the type of light they produce.
The possibilities are truly fantastic; here are just a few:
‘Cold’ white lights are better for concentration than ‘warm’ yellowish lights, so schoolteachers will be able to start the day with an alert classroom. But warm lights calm the pupils down, so when home time approaches, the teacher can just dial up the warmth. Likewise, offices will be able to energise workers in the post-lunch lull. We could do with that here at WHEB!
In a similar vein, long-haul flights will be able to simulate the quality and phases of daylight more effectively, and ward off jetlag. Already the new Boeing Dreamliner will be equipped to do this.
As medical (and presumably, other) growers of marijuana have long known, being able to spectrally tune light allows farmers to optimise crop growth. Combine this with the low energy needs and robustness of LEDs, and there is potential for major yield improvements – and at scale.
Animal health too enjoys the right kind of light. This applies to food animals but also humans. Anyone with experience of a UK winter will be aware of the impact of light on mood and sleep patterns, but the power that these ‘circadian’ (daily) rhythm effects exert on long-term health is quite striking. And there is still more to this: the right type of light can have an astounding medical impact, ranging from treatment of jaundice to, possibly, reduction in some cancers.
The IM WHEB Sustainability Fund invests in Acuity Brands, an American light-maker that is at the front of the evolution into LEDs, and the new range of applications this technology makes possible. There are quite a few other names now emerging in LEDs, and with so much to play for, we’re looking to become more involved as the market grows.