Using 150W halides there may be a push, in the basement cooler temps may run your heaters more eating up the savings. What size tank and PC are you running, should be easy to calculate any savings.
i now have had my 120gal reef for 3 months with acan leds and the whole tank setup costs me an extra 20$ a month. I was very pleased.
the problem with using two of them is you MUST hang em. I couldnt have two combined look neatly over my tank using thier legs. The single unit is sexy and clean.
it really works great...the people at acan lighting are top notch, always willing to help.i did not know that...ACAN always has an answer...very cool and great idea!