I just swapped out my ATI Blue Plus with 2 48" E5 Blues. Very Deep blue, I totally dig them, gives good pop. Got 'em with my ATI Coral Plus. Keeping my coral plus to ensure its getting full spectrum and optimal growth.
So I thought about it. E5 is up to 45% less wattage says Reefbuilder via wattage meter:
Regular 48" 54 watts T5 ($25 @ LFS) use 8 hours/day @ average $0.25/killowatt. Bulb switch every 6 months.
Annual Cost - $50 in bulb changes plus $39 in electrical - $89
vs.
E5 blue pop 48" @ 30 watts T5 LED ($70 retail) used 8 hours/day @ average $0.25/kilowatt. Bulb switch 8 years.
Annual Cost - $70 one time bulb purchase plus $22 in electrical. - $92
Soooo... after the first year its nearly dead even in cost and operation. for the next 7 years of its life span, it will save $17 in annual electricity per bulb and $50 in bulb changes annually. $67 savings per bulb slot per year.
Its late, maybe my numbers are wrong, looks good to me right now...