I use Philips 33W warm white flouros which each give
2250 lumens. Thinking to replace them with leds, I looked at what Philips are offering. Their nearest match is a 20w warm white LED which gives 1521 lumens. So 76.1 lumens/watt for the led compared to 68.2 for the flouro - an 11.5% improvement. The trouble is that I'd need half as many more of the led lamps to achieve the same total lumens. And at 33 each it would take an age to reach break-even. So I'm staying with the flouros - for now at least. Anyone found any better flouro/led comparisons ?
Are not leds though more directional light sources, so how would one factor that into the equation, so an led cluster that shines in all directions might not be what you want. If you can make the light come down in the main, it might not needso many of them. Brian
I was quite tempted to get an LED bulb for the bathroom, but the high price for LED bulbs with a high output put me off.
Tried a CFL in there, but it was totally useless, far too dim. So will stic k with a halogen in a bulb type for now and hope the technology improves (w hich it seems to be doing).
"Brian Gaff" wrote in news:lb6dgh$l5g$ snipped-for-privacy@dont-email.me:
I believe that brighness measurements should be taken by measuring the reflection off a matt surface. Pointing a meter at the light source can give a false idea.
I bought some of Toolstations's 12W LEDs that give 1050 lumens. That works out at 87.5lumens/watt and they are 8 quid a pop, which means they would cost less than half the Philips cost overall. I can certainly believe the claim for brightness as, if anything, they're a bit too bright for many rooms. Although these are directional, in that the top half is opaque, I don't notice the ceilings whee they are fitted are any darker than with other lamps. The best aspect, to me, is the fact that when you turn them on, they come on (!) and not a minute or two later. Must get a few more soon. Of course, they may not be suitable for your application.
Last week I bought 2, 6W warm white LED Osram candle bulbs (from B&Q) to re place 2 40W incandescent bulbs. They are excellent, if anything giving out more light than the originals.
I discovered about an hour ago that for 2014, Philips appear to have completely revamped their product line. The 2250 lumen fluoros that I use have gone - along with many other 240 volt lamps. It seems that Philips have decided to concentrate on the 120 volt American market at the expense of much of their European product line.
I bet it won't be long before the Chinese move in to fill the gap !
You should probably shop around as you can get reasonable (although longevity cannot be guaranteed) LED lamps in the 12W ~1000L class for under a tenner. I have been caught out by one being too bright!
Better prices per lumen are available shop around! No-one ever pays list price for these things...
Only equivalent to a nominal 75W incandescent but this one isn't bad.
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I have had one fail after a year of use which isn't too impressive but not really any different to CFLs failure rate.
If you insist on the most expensive highest possible wattage unit from the most expensive maker and pay full list price for it then yes.
My parents had a nominal 60W equivalent 12W CFL that was getting past its best in their bathroom and I was worried that with its exceedingly slow start they might trip up in the semi dark at night. I replaced it with a 12W LED unit from Amazon for £9 and the result was *TOO* bright.
I settled on a 7W which was perfect. Directionality can be an issue and the lamp shade must provide adequate ventialtion a sealed glass globe will kill them just as with CFLs. Swapping the lights which are most often used to LED will give you a noticeable electricity saving - and a especially if your space heating is not electric. Philips, Samsung and Cree do high power warm white LEDs that have a respectable appearance.
I have some Philips spotlamps in the kitchen an if anything they are slightly too directional. The light was otherwise indistinguishable from incandescent spotlamps.
Longevity still isn't quite there - the PSUs die before the LED go dim. There is a lot of room for improvement in capacitor technology!
It is the only one to have failed so far out of half a dozen or so (all roughly the same age). It has paid for itself on electricity savings.
In the actual well used position that was still break even when compared to an incandescent lamp and slightly worse than a CFL (assuming the CFL lasted tow or three years). eg
2h/day average use
100W = 0.2kWh/day 72 kWh/yr @ 15p/unit = £10.80 vs
10W = 0.02kWh/day 7.2kWh/yr @ 15p/unit = £1.08
So provided the LED bulb costs £9.72 or less you come out ahead even if the lamp is only used on average a couple of hours a day.
People are very sensitive to the up front costs and forget about the hidden running costs of the initially cheaper to buy incandescent.
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