Originally Posted by bk
CFL's use about 25w for a 100w equivalent, versus a 9w LED.
Just on this
The way to measure light is not to compare to incandescent equivalent as that in itself is not a unit of measure, someone may have had a stab at making one but watt per watt some incandescent lamps produced more lumens per watt others.
Some megaman CFLs are delivering 430 - 450 lumens from their 8 Watt lamps. That's a very good CFL, there are many that won't do that
Philips 5 watt LEDs are knocking out about 250 - 300 lumens that's about equal in lumens per watt (this is an industry scale) that particular CFL is actually a bit better than that LED
Like everything else you can have good and bad CFLs you could produce shocking stats for a bad CFL vs a good led
LEDs are certainly better over all , but they also don't last as long as we thought they would and we are ignorant with respect to the rate of output die off that the lamps have because the manufacturers don't have to print it on the boxes.
But 25W to 9 Watt comparison is nearly a 300 percent improvement, that is inaccurate a fairer figure would be to say that the LEDs are about 30 percent more efficient when running, but how long will they last, what's the rate of intensity fall off and how much did you spend on them.
One of the things manufacturers did to produce more lumens per watt was to increase the inrush current . This shortened the life of the lamp, reduced the amount if times it could be switched and considerably reduced the lumen maintenance factor of the lamps, I'll come back to this.
They clawed the maintenance factor back a bit
The "brighter" lamps were great but it shortened the life of the lamp. Some Philips LEDs use to have a 15 year guarantees
That went from
15, 10, 7,5 3, and some are just 1 year.
The lumens per watt went up as the lifespan dropped
Next lmf, lumen maintenance factor what does this mean , more or less if a lamp produces 300 lumens at LMF 50 with a 3 year guarantee, that means that after three years 300 x 0.5 = 150 lumens is considered within the acceptable range of operation
The Philips lamp at say 300 lumens above that I mentioned would have a lmf of 70 so it's acceptable for it to only deliver 210 lumens after 3 years.
Most fluorescent lamps have about a 20 percent fall off. Towards the end of life this accelerates rapidly.
So now we have LEDs that seem like great value but you are going to have to change them more frequently. Yet they kept the good rep for very long life.
I had megaman 7watt gu10s in one room for 5 years. I was glad to get rid of them as they took so long to warm up, but that prolonged the lamp life. The lamps never blew
I recently took 3 number 13 w pl fluorescent lights from my house that were there for over 12 years I changed 3 lamps in that time. I got over 6 years per lamp.
That said I knew what I was buying 12 years ago.
If you take a 6 year old CFL out that has died out by 20 - 40 percent and pop in a new led, the LED will appear much brighter but after six years compare them the led will be the second one and it will be at somewhere between 50 and 70 percent of its original brightness.
In commercial applications to get about 350 400 lux on a desk a good fluorescent set up would use about 10 to 11 watt per M.sq
LED would get 7 to 8 watts per M.sq
You'd still pay about twice as much for the LED fitting as the fluorescent.
The thing about LEDs is that they are dimming very well now and they are much smaller and they look a lot better but no way are they 2.5 to 3 times more efficient than fluorescent.
Hue lamps are great , but you are buying nothing new Imo wrt efficiency you are adding great control and possibly turning them on less, but you might also be washing a wall with green light that you wouldn't have done before. Philips hue has great added value
I've had good LEDs for 3 or 4 years now. One room has never blown a lamp, but one that I have in a pir regularly blew as it switched on and off so much. It would have been cheaper to leave it on 24/7 than pay for all the replacements.
So I'm a big fan of the hue system but not for its efficiency. Advising someone to switch to a Philips hue system for running cost savings is poor advice when your consider the purchase cost. The lamps are very expensive, a Philips hue GU10 is 5 times more expensive than a regular Philips dimming GU10 that costs the same to run for the same output.
We really love it because of the tricks we can do with it.
You get all the tricks but you'll pay for them. And you throw all the electronics away every time you change a lamp just because the led is shot.
In my opinion the colour gu10 at 50 is better value than the white gu10 at 25 euro because it can do so much more with it. I wouldn't bother with the white ones really I'd want it all or nothing