Wednesday, 8 October 2014

So which lightbulb do I buy?

Technology has made so many things better, I won't bother to even describe it because you'd be a determined luddite not to recgnise the fact, and no explanations from me would help you. But an odd aspect of the changing way we have developed lighting means that no-one really has much idea which bulbs to buy now.

We had, as a country, a brief love affair with the compact fluorescent light unit. A great idea in some ways, due to ease of manufacture and efficiency, the quality of light from a fluorescent tube has always been ugly, even with modern coatings  (though OK if bounced off a painted surface). Worse though, they contain mercury, which makes disposal quite specialised and they are NOT something one can just pop in the bin: far from ideal when not everyone can really be bothered to dispose of stuff carefully.

But hot (pun intended) on their heels came the LED. This one-time curio is enormously more efficient than an ordinary incandescent or even fluorescent bulb, but the technology is maturing and developing rapidly. So rapidly that no-one has no idea what kind of bulbs to buy now.

I've been getting a catalogue from CPC for a while, and they supply, among many other things, LED lightbulbs in a wide variety of performances and styles. What we obviously want is a nice simple way to buy light units, and instead of using watts as a guide, instead one should use lumens (the measure of light actually put out). Except that some manufactures are a little more conservative than others, plus there is the issue of colour temperature, since many LEDs actually put a LOT of their light output into the blue end of the spectrum, and a difference of 20% output is not unusual between std and warm white. There are also a lot of older designs around (often quite expensive) with multiple low output LEDs instead of a single large and efficient unit (the multiple small jobs also produce a messy beam & hot/cold spots) and it becomes a bit tricky. Finally, if buying spots to replace small halogen GU10 spotlights that seem almost ubiquitous in modern light fittings, there is a issue of beam width, since the old halogen units have a relatively soft, wide beam instead of the narrow, harsh beam one gets from cheaper LED units (and the older incandescent spots had a softer beam still that was very pleasing and flattering).

This was all pleasantly academic for me until we bought Chris a mother & daughter combined uplighter & spot recently, and had to find bulbs for it. I've been replacing as many bulbs as possible with LEDs, and went straight to our stock of spot bulbs, plus popped in a spare 7W LED screw fitting bulb replacement.

The result, while not exactly dazzling, was WAY too much light, and the spot was like a searchlight. After some fiddling an swapping about I found a GU10 unit from Ikea that struggled to manage it's 120 lumen output for the spot (around the equivalent of a 10-20W halogen unit) and a 20W fluorescent unit for the uplighter (11W would have been enough, but all my 11W fluorescent units are bayonet fitting, rather than screw).

So I'll say again, no-one really has a clue what bulb to buy these days.

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