Soft White LEDs?

With the fluorescent debate in another person’s LJ, I did a bit of research on if Luxeon soft-white LEDs could be an alternative to the somewhat annoying CFB’s that have been pushed recently. I’m discovering though that they’re somewhat lackluster in the energy savings and cost department. 

A Luxeon 3300k 1watt bulb puts out 20 lumens. According to Wikipedia, 40 and 60 watt incandescent bulbs put out 500 and 850 lumens respectively. In raw numbers, you would need 25 Luxeon bulbs to equal a 40 watt Incandescent, and 43 Luxeon bulbs to equal a 60 watt Incandescent. I prefer softer light, the brighter light that CFBs put out hurts my eyes over time.

In a perfect world, that would be 25 watts vs. 40 watts, which isn’t a great improvement in power consumption. It gets even worse when you start shoveling in the extra hardware needed to drive these high-power LEDs. To get a safe, even current to the bulbs (They require constant current, not constant voltage) you need some sort of driver that ties its output to current. The two types I’ve found in my search were both from Luxeonstar.com. One is 95% efficient according to its specs, the other is 80% efficient. The second one can drive 30 Luxeon bulbs and uses 52 watts input. This is equivalent to about a 46 watt incandescent bulb in lighting, and actually uses MORE power. Technically, 80% efficiency should only use 38 watts, but apparently it outputs more than the 30watts that it would need for 30 bulbs. This one works off 110 volts.

The other that is 95% efficient requires a 24 volt AC supply, so you need to add a transformer that decreases efficiency a bit more. They also don’t state their input watt usage, so it’s harder to compare their power usage to incandescent bulbs. In raw numbers, if it is 95% efficient and has no other factors, it’d use 33 watts for 46 watts worth of light. Not exactly a huge leap.

If you use the harsh white light bulbs, then you could get 12 and 19 bulbs to equate to a 40 and 60 watt, but then you lose the benefit of the softer light and get the same harsh lighting that you get from fluorescent bulbs. 



You then run into the fact that the cost is light-years higher than the already high fluorescents. At $3 per light, and $60 for the driver module to power 30 of them… a 60 watt equivalent would be $120 plus the cost of the heat sinks and circuit boards. Bump that up to a 40 watt soft lamp equiv and you’re at $135. I bought a package of 8-10 CFB’s the other day for under $20, and people consider those expensive.