Quote Originally Posted by moeburn
He's right. LEDs are way more efficient than incandescent bulbs, but they're not 100% efficient. Here's the chart:

Luminous efficacy - Wikipedia, the free encyclopedia

An HPS bulb has a luminous efficiency of 22%, while white LEDs have efficiencies from 3.8% to 10.2%, with only prototypes reaching up to 22%.
So, by using LED bulbs for growing, you are spending more money per bulb, and you are going to be spending more money on your electricity bill.

Sounds pretty stupid to me.
You're missing the one major advantage of LEDs here, that being that LED systems only output light on wavelengths that is ideal for plants to use. So even if a HPS system is 22% efficient, about 90% of that light is wasted because the plant can't use it, so really only 2.2% of that light is being used. An LED only puts out light one a single wavelengths, so with them, the numbers are reversed, and like 95% of the light being output is absorbed.

I found another site selling LED grow lights, this one looks a little more promising:

gro-tek.com