Thanks Eric.

Of course those numbers are for 'stable' consumption. Some of those lights consume massive quantities to start up so are only efficient for long periods of illumination and are not cycled on and off. That said, efficiency MUST take into account application.

I don't need massive amount of lumens for my application. I need the minimum amount of power consumption for the amount of light that I'm comfortable with & LEDs answer that well. When I want to illuminate my back yard like there is a massive solar flare occuring - I turn on my mercury vapor light and like magic, 30 minutes later I'm getting a sunburn at midnight.