Light bulb life incandescent vs LED

[ianab]

I wouldn't discount the value of the power savings. Even if it's only 30watts, over 25,000 hours that's 750 units of power.

Not sure what your power rates are, but if it's 10c a unit, that's $75 of power cut to ~$7.50. OK it's only a few cents a day, but over ~10 years it's going to add up.

Even more saved when the lamps are on full.

[Alex Grigoriev]

If you have tiered pricing for electricity, and are hitting the higher tiers, any savings should be accounted on that price, which could be over 50c/kW*h.

[Cooler]

Lutron gave a rather detailed response which I quote in its entirety below.

It explains why I cannot dim it to very low light levels, but I will have to await the Cree response for expected life of the dimmed bulb.

Good Afternoon Packard,

Thank you for contacting today. The dimming range of LED’s will depend on both the bulb and the control. Many LED bulbs are not capable of being dimmed below a 10% measured light level, regardless of the control used. Incandescent or halogen bulbs will dim to 1% on most dimmers. There is also a different between measured and perceived light output. Measured light is the amount of light as shown on a light meter. Perceived light is the amount of light that your eye interprets due to dilation. For example, 20% measured light equals 47% perceived light. For more information see Measured vs. Perceived (PDF).

Bulbs on our Compatible Bulb List must dim 20% or below to make this list. The LEDs on this list have passed compatibility testing with the dimmer model number(s) that appear at the top of the page.

If you would like to know the exact measured and perceived percentages of tested bulb you can use our LED Product Selection Tool. Select your preferred lamp type and use CL Dimmer as the control type. You can select a manufacturer if you prefer a shorter list and hit search. A list of the tested bulbs will appear at the bottom of the page. Click on the orange link under product name (the model number) to get a report card and detailed information on each LED. The report card will provide you the dimming details of this particular bulb.

I hope this helps.

Sincerely,
Katie
Lutron Support
Lutron Electronics, Inc.
www.lutron.com
www.forums.lutron.com
KH

[ianab]

One difference is that LEDs are more efficient at low power, where incandescent is less efficient.

If you run a LED at 1% power, it will still make noticeable light of the same colour, where a filament wont even glow orange.

Also, LEDs are very voltage dependant. If it's a 3.0V diode, at 2.9V it's barely lit up, at 3.1 volts, it melts.

So it's not that the LED can't be dimmed, simply by controlling the current though it, but it needs to be done in a somewhat different way to a filament bulb. Using a "dumb" LED with a regular dimmer isn't going to work. Either the LED or the dimmer circuit needs to be much cleverer.

[ianab]

Well the supermarket had LEDs on special, and we needed a couple of spares to replace some CFLs that are dying of old age.

So far so good. 12W Phillips LED in the lounge, and it's giving out good light. To be fair it replaced a 5 year old 24w CFL that was getting a bit sad.

Compared to an incandescent? 10cents a day in power savings pays for the lamp in 6 months. So if it lasts a year, I'm ahead.