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Most efficient grow?

Discussion in 'Grow Room Design & Setup' started by petwar, Feb 22, 2008.


    petwar Active Member

    Just wandering who has had the most energy efficient grow. A while back I tried 4 plants under 3 x 58watt 60" (before the days of Envirolight) aquarium lights and managed a meager yield of around 120g (4 ounces?). I had a bad space with lots of light leakage, just in soil and a painfully long growth period (about 5 months from wetting the deeds).

    My dates and times are a bit sketchy to give an accurate figure but a g/Kwh figure is easy and gives you a really good idea on how well a growroom is working in terms of it's main power usage (not including pumps, monitoring equipment or anything else)

    So say I vegged for 2.5 months and flowered for the same and produced 120g dry weight.

    (Wattage x Hours Used Per Day) / 1000 = Daily Kilowatt-hour (kWh) consumption
    (1 kilowatt (kW) = 1,000 Watts)

    Veg: 174Watts of lights, 24 hours a day.
    (174 x 24) / 1000 = 4.176Kwh per day

    2.5 months =(ish) 76days.
    4.176Kwh x 76 days = 317.376Kwh used.

    Flowering: (174 X 12) / 1000 = 2.088Kwh per day

    2.088Kwh x 76 days = 158.688Kwh used.

    Add those together for total power used and divide by dry yield in grams:

    (317.376 + 158.68) / 120 = 3.9672 Kwh/g

    So each one gram joint cost me 3.9672Kwh and about 48p in electricity. If thats a bench mark then someone should be able to beat it. I've heard as high as 10 Kwh/g is possible but never seen one.
    The search continues...
    heady yeti

    heady yeti Member

    like the thought process
    Bob Smith

    Bob Smith Well-Known Member

    You need to somehow factor quality into that equation - if I wanted to, I could try to have my 1000HPS cover 50 square feet (and it would, although not very well), but the majority of herb wouldn't be very good.

    No offense, but (without doing the math) I'm thinking that fluoros are technically going to be "more efficient" (by your standards), but I'll take some HID herb all day.

    Just my $.02.

    Canabud Member

    I never thought of measuring that way just Grams/Watt of flowering light maybe ill calculate my next yield this way too. Wouldnt 10 kwh/g be way less efficient? my goal is to have the highest yield with the least amount of energy. I could flower 1 sog plant under 2 1000w lights and say it took 20kwh/g but would be a waste of the light.
    Bob Smith

    Bob Smith Well-Known Member

    To say your goal is to "have the highest yield with the least amount of energy" doesn't take into account quality at all, which was my point in my previous post.

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