We have been on a helter-skelter ride of new lighting technology in the past several years, all of which has promised greater and yet greater savings of energy. Most
of these have turned out to be over-optimistic promises backed by numbers that bear scant relationship to reality. It has become pretty clear that we do not know with any degree of certainty how much electrical energy is directly used by lighting let alone what extra energy is needed for ventilation and cooling to get rid of the heat produced by lighting.
It is also clear that daylight has become an enemy of buildings through the heat loss through windows in the winter and uncomfortable heat gains in the summer. So, rather than optimise window design, building regulations insist that no more than 40 per cent of a façade can be glazed.
Profligate use of lighting
It seems pretty obvious that the most efficient electric light is one that is switched off. Despite this we see profligate use of lighting when it is not needed, in commercial buildings after working hours and even in our own homes because many people just don’t switch lights off in rooms they are not using. This is a psychological issue and a learned behaviour. We have evolved into a species that sees fire and light as indicators of safety and comfort so we have to be specifically trained to plunge places into darkness.
What we need is simple and effective controls that will switch light on. We would arrive in lit spaces that feel comfortable rather than edging into dark spaces while the lights decide whether or not we are there and take whatever time they take to switch themselves on.
At present the majority of lighting controls are entirely reactive, switching light on after we have entered a dark space. What we need are controls that will switch the lights on before we get there. We are saddled with, by and large, PIR technology that we picked up from the burglar alarm industry. This is really not very good at determining presence, it is all designed to detect movement, hence the infuriating distraction and arm-waving required to switch lights on when the inadequate detector has not seen you move for a while.
What we need is something a lot more sophisticated based on other technologies that exist already. Digitalcameras are very cheap, so are computers. They are used extensively in manufacturing to monitor parts moving on production lines, for robots to accurately fit things together and were even demonstrated by Philips as lighting control devices some three years ago at Frankfurt. Why can we not have these operating our lighting? Identifying presence by shape and colour, switching lights on in corridors as we walk towards the door, providing task lighting by determining what we are looking at… With little modification such a system could recognise us individually and adjust lighting to the way we like it.
Offer us convenience
Please can the lighting industry start working on these technologies that offer us real convenience and proper energy saving and stop messing about trying to re-invent the light sources that are already doing pretty well in changing electrical energy to light?
Can the regulators stop looking at meaningless numbers and start to encourage the use of daylight rather than electric light?
Finally, can the researchers start to look into some real numbers on energy use of lighting and do some proper research on the psychology of the use of light? Changing one lamp for another is not going to produce the massive change in lighting energy use we need to meet the challenges of climate change. It might look good in terms of being seen to do something and it certainly boosts the profits of the lighting industry. It does, however, consume other resources that are all contributing to human impact on the ecosphere.
Once – and if – we solve the energy issues, we will have found we have dug ourselves another hole in the planet.