Tuesday 15 March 2011

LED kitchen lights

Are now possible - but not very good, although MUCH better than budget compact fluorescent spots. I guess the best of the new Cree and Seoul LED units haven't made it through to mass manufacture yet, and these things are obviously not very efficient from the sheer amount of heat they generate compared to the high efficiency units.

The other issues - poor lenses and colour temperature - could do with some more work as well. An incandescent spot light has a bright single point of light, and is focussed by collecting the light in a reflector, which helps provide a softer, more diffuse beam because the light is directed from a wide area. An LED produces light from a flat surface with a spread of around 120 degrees, and is usually focussed with a lens. This produces a hot spot instead of a smoothly distributed beam, and also results in hard shadows. In addition, LEDs still tend toward a blue-white light with a colour temperature around 5000K or higher, rather than the warmer light from an incandescent unit at around 2500K to 3000K. These 2 characteristics combine to make the lighting harsh.

Warmer colour temperature light units are available - we have a 3W Philips unit that starts off with a pinkish colour until the unit has warmed up and the colour caste diminishes. But that's not *quite* bright enough, and was horribly expensive.

A week ago I bought some of these, and although they're bright enough, they have all the faults I listed above. The hot-spot issue can be dealt with by removing the plastic lens, but the light then spreads a little too far. Next up is to create some better diffusers using photographic warm-up filters (I should have some laying around, somewhere) and maybe extend the reflector outward to reduce the spread and improve focussing.

It was tempting to return them as simply not very good, but I'd rather make them work (and save a lot of electricity - 6W instead of 50W per bulb) and also reduce the number of bulbs we have to replace. Because the supply here is unstable, continual voltage surges cause the halogen bulbs to fail quickly. We have probably replaced about 15 bulbs over the last 12 months, which is enough to pay for the 4 LED units we just bought. That gives us quite an incentive to make these things work.

Incidentally there are a LOT of different bulb replacements available - some for as little as £5 on ebay, some as much as £28, and all of variable effectiveness. The Jobs made up of lots of tiny LEDs really aren't worth a wet slap, other than for 'decor' lighting.

No comments:

Post a Comment

Play nice - I will delete anything I don't want associated with this blog and I will delete anonymous comments.