there are some other factors also,your going to be switching from 18/6 so one month its going to be much higher. call your power provider and see if there is a limit on kwh before the charges go up. for example,i use pge and i am alloted a base number of kwh at 16 cents a piece,but when im in 18/6 my bill damn near doubles because i pay upwards twards 29-30 cents a kwh.its bull shit.if you live in the bay area to run one 1k 18/6 is ruffly 90 to 110 bucks.u might consider using 3 600 watts if you have the cash to buy an extra lamp,great light coverage,cheaper pge,and u dont loose 2 many lumens.oh yeah and much less heat than the 1000's:thumbsup: