The two hagen filters are about 6 watts each, couldn't readily find the power consumption of the other filter, but assuming it's the same you're looking at a total of 18 watts.... At 18 watts you'd run for 55.5 hours before burning a kilowatt. Look at your KW charge to figure it out from there... In much of the US it would be about 5-6 cents a day to run all three filters.