LED growlights!!!

[loaches r cool]

I'd have to say that it would never pay for itself in the long run. The efficiencies are still not very good and the unit is rated only a few times longer life than most fluorescents. When you figure in the cost of fluorescent bulb replacement it is still way cheaper. Here is a quote from their site:

The current design produces PAR light output levels equal to a 250W MH 20K. It uses 40% less energy than the Metal Halide Fixtures it replaces. The life of the LED's is 50,000 hours, so it almost eliminates metal halide and fluorescent bulb replacements. All heat is radiated up and away from the tank Therefore, it does not heat the water like Metal Halides or Fluorescents. This eliminates the need for Chillers. The room air conditioner needs to work 1/2 as much since the light fixture produces only half the heat of Metal Halides which saves even more energy over traditional lighting methods.

They are comparing the efficiency and PAR levels to a 20K MH, sounds like their trying to trick the unsuspecting reader. A 20K MH is usually horribly inefficient at producing PAR per watt. Something like a 6500K MH can easily be 300% more efficient than a 20K. For example looking at sanjay joshi's spectral plots a 6500K Iwasaki has a rating of 110 and a 20,000K Giesmann is 38. And some now say that T5HO is even more efficient than MH. And you can buy 54W T5 bulbs for under $15 that usually last 2 years or more and are great for growing plants. Just my $0.02