21 Nov 2014

Lighting the future

I visited LuxLive on Wednesday to see where the lighting industry is headed. As you might expect, it can be summed up in 3 letters — LED. They were everywhere and there was very little of anything else. For someone used to writing about construction, where the pace of change is lugubrious, it's quite exciting to see an industry undergoing a rapid transformation. For most players in this space, it is a question of how to add value to a product which is both dropping in price and increasing in quality all the time. It's not enough to just sell LEDs: the future market is just too unpredictable.

And many so-called experts turned out to be almost as clueless as me. I was told on good authority that dope growers have no use for LEDs because they can't do ultra-violet light. A quick Google afterwards revealed dozens of really cheap UV LEDs. In fact, we may be about to be entering a world where growing all manner of plants at home becomes a whole lot easier and more productive.

For the past ten years or so, much of the emphasis in the lighting industry has been on increasing energy efficiency both by squeezing more performance out of the lamps themselves and by adding better control gear and better design. The arrival of cheap and very efficient LEDs has already made much of this work look pointless. Cree, the NASDAQ-quoted LED powerhouse, have now produced an LED that delivers 300 lumens per watt, which is about eight times more efficient than the best compact fluorescent, and although it's not yet in commercial production, it seems just a matter of time before the bar is raised again. In five years time, maybe 1,000 lumens per watt will be possible. By then lighting will have become so cheap to run, that it will be nearly-free. An old-fashioned 60-watt bulb could be replaced by an LED running on less than half a watt. A whole house could be lit by as little as 10 watts at a cost of maybe £5 per annum.

Not that LEDs are without their issues. The light itself is produced from a very focussed source which means there is a glare issue. Lots of work is going into shielding and diffusing this glare and making it more acceptable in every application. Backwards compatibility with existing light circuits is not always guaranteed and there are issues with dimmers not working with LEDs though, again, technology seems now to be producing LEDs that will work with existing dimmers.

One of the neatest and simplest ideas I saw was at the Megaman stand where they had adapted a dimmer so that the colour appearance of the lamp got warmer as the light level was decreased. I'm not sure this is commercially available yet, but it seemed like a very simple way of addressing the issue of the colour appearance of the lamps which exercises some people quite a lot.

The future of cabled switching also seems to be in question. Lots of stands had wireless switch plates for lighting and Megaman were also displaying a wireless home automation system which allowed you to control the heating system as well, all from your smartphone. If this is really advantageous remains to be seen — I think most people will still want a physical switch or thermostat as well, if only because smartphones get misplaced or run out of battery or break down. Wireless switching really comes into its own when you want to pre-program your lighting or heating or switch it remotely, but how many people actually want that function? We will see.

In the meantime, the wireless switchers are not being helped by a protocol turf war rumbling away in the background. Wi-fi v Bluetooth v ZigBee v Z-wave. It's all very well have Z-wave enabled kit, but how do you know the world won't have gone fully wi-fi by 2025? You could end up being Betamaxed, although, to be fair, you won't exactly run short of content, so it may not be quite so critical as all the existing protocols will be supported for decades, even if they stop being used for new applications. Nevertheless, it doesn't help matters that it isn't clear which home wireless system will prevail.


  1. The effect on PassivHouses - no incidental heat gain any more from lighting; heat emission from appliances heading the same way; low energy cooking coming. PH 'supplementary' heating systems working harder, longer and/or much higher standard of insulation/airtightness etc, to hit the energy demand targets unameliorated by incidental gains.

  2. We aren't going to get to 1000 lm/W. The theoretical limit is 783 lm/W (when all the electricity is converted to light and no heat is output). So at 300 lm/W we are at about 40/60 light/heat. Which is a dramatic improvement from my first white LEds, which were 7.5 lm/W (worse than a halogen bulb) back in 2000.

    But yes all lighting will be LED eventually. The sooner the better in general. Pity Cambridge is busy replacing all our streetlights right now with not-LEDs. Missed opportunity there.