Bye bye HID light

While Ceramic Metal Halide and halogen lamps are inexorably being pushed aside by LEDs, which outperform both on most counts, Gary Heald warns users to do their homework before moving over, as disappointment may lie ahead

As of last year new-generation, high-output LED luminaires became available, marking the start of the decline of Ceramic Metal Halide lamp as a display light source.

It will not be a particularly slow death. Within two years only the most blinkered user or specifier will be installing CMH. Indeed, by this time many of the larger users will be taking out existing fixtures and replacing them with more efficient solid-state luminaires.

CMH came to the market around 1994. Many large, high-street lighting users with huge amounts of display space were quick to adopt it because at that time the only alternatives were halogen sources that had proved inadequate.

Initially most used dichroic lamps for spotlighting. A relatively short lamp life meant the estate managers were never happy; they were constantly changing large numbers of failed lamps and the CMH solved this problem. Although the light quality was not as good as halogen and cost a lot more, CMH lasted much longer and as energy was starting to cost more, there was a payback story.

Now most, but not all, of the property departments were happy. But many users were unhappy and are still not happy with the light quality of CMH. While suppliers claim a CRI of more than 90 measurements in R9 (red) are very low, and despite a much longer life lumen depreciation is relatively quick, so a new lamp after nine months looks and performs significantly less well. Lamp changes become a very expensive monthly requirement unless you pay the huge one-off cost of planned maintenance.

Halogen remains popular in markets where energy is cheaper and is still used by many 'high-end' users to display couture or luxury goods for example, or to illuminate museums and galleries. This is because despite significant improvements, CMH is poor in light quality and consistency.

Tungsten halogen light sources have a sparkle, a joie de vivre and vitality that engender a romantic attachment that many people will miss. And as no one likes to be told what to do, many will resist the directives to remove products from the market. In short, we all like dichroic lamps, which is why we took them into our kitchens and bathrooms. By contrast, the only people who will lament the passing of CMH lamps are the big manufacturers and lamp wholesalers who will miss these huge cash cows.

Despite the belated discounts now being offered, nothing will halt progress. Ceramics will not be pushed aside by regulation as halogen is, but will be shunned by the users who recognise better efficacy, a large improvement in light quality and significant maintenance savings as far better value for money.

We have been witnessing a relatively quick change in a nationally slow-moving industry to LED products, but we are now at the very cusp of mass adoption. LED luminaires at their very best match halogen for light quality and surpass its consistency while outperforming CMH in every way; we measure performance consistency, quality and longevity.

This new technology is not as expensive as some would have you believe, but users beware - the majority of all new LED luminaires in the market may disappoint. LED is a generic term but performance varies more than any other light source you have ever bought. At best, LED performs way beyond anything that has been available before, but many products, even from well-known manufacturers, will disappoint. More than at any other time, companies will need to do their due diligence before investing, as many lighting companies appear to have very little idea of how LED lighting works. I imagine that for a user this task could prove almost impossible, but it will have to be done because right now linear LED products surpass the efficacy of the humble fluorescent lamp - 107 against 92 lumens per watt, despite only costing £3.

In two years' time, the relatively inexpensive fluorescent tube will also start to be replaced in large numbers as energy costs spiral upwards, while the LED efficiencies increase. Over the next two years LED efficacy will rise another 40 per cent as more light and less heat is produced. That is why within this time frame everyone will be buying LED fixtures.

The future of the luminaire industry will belong to the companies that can read, adapt and embrace this solid-state future.

This article was first published in fx Magazine.

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