Look at your power bill. We are charged X amount of money per kilowatt consumed every hour. If you use 100 watts of cfl it'll take you 10 hours to be charged the $0.xx. last I looked the most expensive in the nation was about 25 cents so it'd be 25 cents every ten hours that the light is on. Have to add in fans and whatnot too, just look at them and add up their consumption ratings, my bet is they're under 100watts for a small grow as well, so 50 cents every 10 hours maybe? Edit. I'm bored so I googled quickly and found this quote. Texas is the energy capital of the world, giving Texans cheaper electric rates and more electricity options for their homes and businesses. Sounds like it'd be safe to assume you are charged under $0.15/kwhr
where did you come up with 10 hrs? I run a 1000 watt hps, 2 fans and air pump for a 12/12 flowering schedule and it costs me about $40 eaxtra per month. Cfl's wont even register compared to that.
I had a 400w mh, 2 fans (house fans) running and so often a 440 cfm fan and my bill was 15$ more roughly. 5cfls with some cpu fans should do like 10$ max imo
If using 100watts of power per hour it'll take the appliance 10 hrs to use 1kw. I agree ~100 watts won't compare to 1000watts, where did I say it did? I just gave the man an example of how to work the problem out himself since without knowing how much his electric rates are no one can answer his question.