My power bill was between 250.00$ and 350.00$ per month before I started to grow anything.. Now I'm using 2x 400w HPS and 4x 125W CFL's..plus multiple fans, carbon scrubber and de-humidifier.. What I did just before I hooked up my set up were these things.#1. Replaced all bulbs in my house with flourescent replacement bulbs. #2. Put my heat/cool thermostat on a programmable timer to automaticaly adjust temps when I am not at home. #3, Removed my 400w Metal halide that I was using to light my 130 gal fish tank and replaced with 2x 6' marine glo/and 2x power glo flourescent.bulbs. #4 put my pool filter/pump on an outside timer to only come on for 5min every hour when it is dark outside.. Running all my CFL's on 24hrs and my HPS on 12hrs my new hydro bill was under 300.00$.. That to me was shocking.. Its less now then when I wasnt growing anything..