Megaman GU10 - any good?

[shambles]

I have just bought a couple of Megaman GU10 11W cold-cathode lamps to replace half of the 50W tungsten lamps I had in my kitchen.

The ones I have are here: http://www.megaman.cc/global/products/product.php?sid=4

First impressions in the real world is that they are not quite as bright as the conventional lamps, possibly because the light they produce is more diffused than the tungsten versions. But for my situation, they are bright enough. The 11W versions are claimed to be equivalent to 50W - I don't know about that, but they are certainly bright! The package suggests the ones I have are warm white. Interestingly, one of them looks a bit warmer than the other, but neither produce as warm a light as the tungstens - they look a bit blue/lilac. They are a bit slow to warm up - next to useless for 20 seconds or so and reaching full brightness after about a minute.

I personally don't think they are quite good enough to do a complete replacement for the tungsten lamps because of the warm up time and the colour they burn at. But two of these will reduce the energy need for my kitchen lights from 200W (200W!) to 122W so I am happy to have them replacing the lamps that are doing area lighting, keeping the tungstens for lighting the cooker and the sink. They are available in my local lighting shop for £9.00 - on the net they can be found for less. They should last for years, and they look pretty good - only a little longer than the tungstens.

My advice to anyone looking at these things, whatever brand they are, would be to ask for a demonstration where you can do a direct comparison with the standard bulbs. And don't give up on them - they may not be brilliant right now, but next year the technology might have improved. You might think these are not a direct replacement for all your tungsten GU10s, but used alongside the conventional ones, they might be OK...

[rjrl101]

I've got four of these in a bathroom and I really like them. When I first got them, I only installed two so that I could compare them to the existing gu10 bulbs. Like you, I found them to be not quite as bright (but almost) and that they definitely produce a colder light than the traditional gu10s they were replacing. However I prefer the colder light and thought that the old bulbs emitted a rather unpleasant yellow in comparison. Within 24 hours I'd changed the bathroom completely over to the Megaman gu10s. Very impressed.

I find that they emit a low but perfectly useable level of light at start-up and as general rule, I've found that if I can't see in the room when I first turn (slow-start) energy saving bulbs on, the room is under-lit and more light fittings or more powerful bulbs are needed. Also, I find they come up to full brightness a bit quicker on second and subsequent uses each evening. I guess they hold their heat well or something.

Another rule of thumb I use is, the longer the energy-saving bulb's advertised lifespan is or the more expensive it is, the longer it will take to warm up. I think Megaman advertise 15,000 hrs for theirs while those Philips bulbs that can be bought for a bit over a pound on the net start up very close to full brightness but only claim 6-8000 hrs of life.

Richard

[shambles]

''Another rule of thumb I use is, the longer the energy-saving bulb's advertised lifespan is or the more expensive it is, the longer it will take to warm up. I think Megaman advertise 15,000 hrs for theirs while those Philips bulbs that can be bought for a bit over a pound on the net start up very close to full brightness but only claim 6-8000 hrs of life.''

That's worth knowing...

Since my last post on these I have noticed that they seem to be getting up to a useable brightness more quickly than they were when I first had them. Also, the colours have evened out, although they still remain a bit too blue for my liking. Like you, I am impressed...

[wookey]

LEDs are going to be be the answer here. Last year's Seoul P4 3W LEDs (See http://www.molalla.net/~leeper/seoulmy.htm for a geek's view of these things) put out about 280 lumens at 3W which is an efficiency of 85lm/W. A halogen bulb is about 15lm/W. Instant start, dimmable down to pathetic levels with no loss of efficiency, and very small. Bluer than halogens, more like daylight, and these early ones tend to go bluer as they age, but this stuff changes by the month. I assume we should be seeing bulbs in standard MR16 form factor containing these LEDs and a driver circuit about now. I just bought the LEDs for 9 euros so a finished device should be about 10-15 quid, but so far consumer LED devices seem to have been resolutely expensive. Still, now that they are more efficient than CFL, even allowing for the driver electronics, the instart start aspect should make them quite popular, and that should make them cheap in due course (as it has for CFL bulbs).

The tricky bit is going to be heat-sinking. The MR16 format does not make it easy to dump heat, and that is important to give these devices long life. Purpose-made fittings will be better in the long run.