I don't think they are as big of a sabings as people think
~introducing fish and coral into a electronically balanced body of water since 2007~ said:
The savings depend on what you are running currently. The above fixture has 56 3 watt leds running a total of 168 watts, even a 150 MH bulb will use more energy when you factor in the start up current surges along with the 9-12 month replacement cost of the MH bulb. You also take into account any additional cooling method's you may no longer need 100% along with less top off water needed. You also can program your home AC to run warmer when noone is home. There are a lot of small thing's that add up when running MH's.
Cheers,