how to use the smallest amount of electricity possible ?

Check out a CFL grow. Very small impact on your electric bill.

You can get started here...

http://forum.grasscity.com/general-indoor-growing/122824-kamels-cfl-guide.html

Good luck.

 

Wrong way to look at it. You are trying to maximize your grow, right? You want the biggest yield, the most potent bud, etc.

So...any time you ask how to do your grow with the least, the cheapest, the minimum, the smallest, etc you are introducing a self-defeating variable.

The smallest amount of electricity possible would be to run no lights and no fan. Yes, the plant will die, but you will have met one of your two goals beautifully. That, of course, really isn't what you want or what you're asking. Unfortunately, we can't tell you what the perfect trade-off would be for those two competing goals, only you can determine what is the perfect trade-off for you.

CFLs can use less electricity, but not always, and using them can affect your yield.

For your size space and number of plants you could do a 250w HID, an excellent light source that will grow 2-3 plants very well, and that would add perhaps $10 a month to your bill during flower cycle. Now you have something to analyze and consider.

 

I agree with this guy. For real, cfls may be less power hungry, but the trade off is you need to use more of them. For normal lighting they are great because you only need to see by them, you are not a photosynthetic creature so you. Use a higher power HID, it will cost about the same, and provide you with more lumen output for your buck.

 

The 400w HPS light I use stays on for a solid 15 days a months and only impacts my electric bill by $20, but you can get a totally decent harvest of potent bud using only CFLs and/or shop lights (not as big a yield as HID lights obviously but still respectable).

And since the fluorescent lights produce much much less heat, you may be able to get away with not having a vent fan.

 

Go here Advanced Nutrients | General Hydroponics | Hydroponic Supplies

for electricity costs..

I'd just get a 250w or 400w considering what your gonna grow...

You wont start a fire with a hid set up.

You might start one however trying to hook up some shoddy light fixtures to try and save money lol.

 

Anything to help a fellow grower

Good luck with your grow

 

HIDs do run hotter than CFLs, so the challenge is to figure out if and how to handle that heat effectively. You will need to exhaust it to somewhere, you definitely cannot leave running lights of any kind in a closed-in closet and not expect some heat build up.

The best solution is an air-cooled hood, which runs a separate ventilation path through the light fixture and whisks the heat away, leaving the grow space much cooler.

 

He is right. Heat build up happens, even with CFLS. I am running a small closet with 4-100watt(or 13w eqiv) with a 70watt HPS and I have had major issues with heat. Now note, that this will not start a fire(highest heat I had was 92f) but it will NOT help your plants out any. Just get two small computer fans. One for the intake, and one for the outtake(make sure your out take is twice that of your intake). I only had one for the out take, but once I got the smaller one for the intake(and had this pointed at the lights) the box stays at around 78f.

 

Dug has posted a thread in advanced grow techniques

http://forum.grasscity.com/advanced-growing-techniques/398686-boosting-growth-electrical-
stimulation-w-pv-cells.html

I read through it and if it does work as well as claimed you'd be able to save a significant amount on the electricty for lights. otherwise use led's or cfl's and use a veg light schedule of 18/6 or 20/4 to save cash