Someone give me some variables and a rpugh guestimate please. Thanks.
about 70 bucks for light 12/12 about 120 for 20/4. best off to get a hps as its more efficient than mh and will give u those tight hard hydro buds.
Someone already did. I'll try to break it down just a little further.
A 1000w HID light gives 1000w of power to the light, but consumes something in the vicinity of ~1040w (I don't know the exact number, and digital ballasts are more effecient)
at 18/6 for veg, you can assume about 560 kWh/month
at 12/12 for flowering you can assume about 375 kWh/month
kWh pricing varies according to company that sells it, time of use (off peak is cheaper), and any taxes your area charges them that they pass down to you. I average something in the vicinity of 10 cents per kWh. I had this post typed a long time ago, left the house and forgot about it, so if it was already answered my apologies.