A radical approach to truly effective lighting

Efficiency is no guarantee of sustainability

Those designing lighting for a space need to choose carefully where to illuminate, and to think in terms of the illumination that’s achieved in lux/watt rather than the efficiency of the light fitting in terms of luminaire lumens/watt. Specifically, what’s being advocated is a combination of low glare, precisely-targeted task lighting and a general movement towards the illumination of vertical surfaces over the floor. It’s about directing light exactly where it’s needed for tasks and where it’s most effective for human perception – and reducing it everywhere else.

This reduction of light in certain places is balanced by an increased emphasis on people-centric lighting designed for visual comfort. A key part of this is switching the focus from the floor to the vertical surfaces. To make a space feel bright, the walls need to be illuminated as that’s what’s in the visual field.

‘If 100lx is put on the wall instead of the floor, the room feels three to five times brighter – just by illuminating a different surface.’

Better lighting with half the energy

Historically, walls haven’t been prioritised, although the latest version of the European indoor lighting standard EN 12464-1 now takes it more seriously. In an office, for instance, the strategy of guiding light where human perception requires it would dictate that light is delivered to the desktops, if that’s where light is required. In a 100 square metre office, desks could take up 20 square metres of the space. If you light the walls and the desks only, then compared to uniform blanket illumination, about half the energy could be saved while creating a better and apparently brighter visual space for people.

ERCO spotlights, by contrast, use lens systems with single high-powered chips. This tiny but bright point of light is much easier to control into a narrow beam of effective light. ERCO mounts the chips themselves into their own printed circuit boards before pairing them with a bespoke lens design. Although this construction has nominally lower lm/W values, it brings up to 20 per cent more light to the target surface compared to rivals. This means that planners who only look at the lm/W values on a luminaire's technical data sheet are giving away the potential for sustainable lighting focusing on more light on the target area as well as for energy savings.

The combination of effectively targeted light and high visual comfort for people may sound simple at first glance, but in its implementation it can be radical. But with the climate crisis looming, and those lumens no longer cheap, a radical approach that recalls perception-oriented lighting design with high visual comfort is probably just what is needed.

Find out more about sustainable lighting with ERCO Greenology.