Is your office lighting actually costing you money?

I usually calculate a return on investment on our lights of three months. Our lights are now €300, and within three months you get that back in terms of improved productivity. We use an AT&T Kearney study, for example, that says up to 4.5% improved productivity. And in school vision studies by Philips, they see a 20% improvement in pupil scores while having 45% less stress and making fewer mistakes.

So there are really good upsides on the productivity side. But even if you take productivity out of the picture, absenteeism decreases as well with better lighting. One day of absenteeism costs €600 on average, and better lighting reduces absenteeism by roughly one day a year on average. Those savings are also deductible, and then you're looking at a six-month ROI.