How to Light

How to Light: How do we know an LED spec provides value for money?

A reader had a question regarding the commercial evaluation of an LED lighting framework. ‘How can we ensure we do not end up with the cheapest suppliers? Asking suppliers to quote for a mini project, or asking them to provide project rates, would still result in the cheapest offer scoring highest.

‘Of course, there is the written quality part, and while this can be a greater percentage of the scores, I am still very aware that suppliers with the cheapest rates could simply inflate their product performance figures. Do you have any recommendations in terms of how to ensure the quality of the lights being supplied?’

Manufacturers will, inevitably, put a spin on whatever data they provide, so it’s important to get knowledgeable, independent eyes looking at whatever proposals are put in front of you. This is about looking behind the numbers and making an assessment of how realistic the manufacturers and suppliers have been in the proposals.

A comparatively recent trend is the introduction of the effects of time into performance data. Before LEDs, we all knew roughly how long light sources would last, so ongoing maintenance could be costed with that in mind. And, let’s not forget, replacing a lamp was like hitting the reset button, more or less giving you back your original installation. But if someone tells you that an LED fixture has an operational life of 50,000 hours, it raises a few questions.

1. How does 50,000 hours translate into real life? (One hundred per cent usage would only be five years and nine months, after all.)

2. What happens at 50,000 hours? The light doesn’t just go off; the figure is based on deterioration in light output to – what? Seventy per cent? Eighty per cent? Ninety per cent?

3. What happens to the fixtures at 50,000 hours? Do they need to be completely replaced, or is it a cassette-style design that enables you to keep housings, only replacing the electronics?


Supermarkets, county councils and other big estates are trying to lock companies into long-term contracts, guaranteeing that the fixtures function throughout their life as stated in the original bid. That’s OK if you can ‘guarantee’ that the supplying company will still be around if and when the fixtures start to fail early.

Lighting designers and consulting engineers – those of us who are independent of the supply chain – will always say that the cheapest is never the cheapest. My colleague at Lux, Alan Tulla, puts it succinctly: ‘Buy cheap – buy twice’, and that truth blows the RoI for a cash-starved budget straight out the window.

At the end of the day, the cheapest scheme will be the most reliable. It will not have required any emergency call-outs, ad hoc fixture replacements or component failures – and it will have provided the required light performance throughout. And it’s highly unlikely that this will have been the lowest-cost fixture on offer.

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