hes running 25 plants in a 4 x 4 Link = https://www.rollitup.org/t/500w-diy-led-4x4-organic-2-15-lb-grow.952567/#post-13882395

Actually do your research us COB growers have been hitting 2 gpw for over a year now and no that is a 4x4 each 4x4 get 2 meanwell drivers at 250w each and 16 Vero cobs I run 25 plants in each 4x4 tent that's only 1.3 oz per plant. Let me see your flowers at week 4 here's mine

Gpw isn't accurate at all but it's what most people understand easier than explaining PAR n LuX. And my thread was just to keep it simple and show what you can do with very little power. And it's real easy to explain the total yield divided by the light output of just the light system, instead of like kwh.

I'll try to explain my thoughts on the whole gpw not seeming as accurate as kwh the best I can. Example- You have 2 growers both using exact same room, strain, plant count, equipment etc and both pay .10 per kwh: (1) HPS @ 1000W (1) 5000 btu A/C unit @ 500W Grower 1 veg's for 8 weeks (uses either seed or from rooted clone). @ 18/6 thats 18hrs x 1000W = 18,000 watts per day. Divided by 1000 x 60 days veg time = 1080 total kwh used in 8 weeks veg time. Grower 1 flowers for 8 weeks. @ 12/12 thats 12hrs x 1000W = 12,000 watts per day. Divided by 1000 x 60 days flower time = 720 total kwh used in 8 weeks flower. Grower 1 uses A/C for 16 weeks total. It cycles for 20 minutes per hour when lights are on during veg so: @ 6 hrs per day thats 6hrs x 500W = 3000 watts per day. Divided by 1000 x 60 days veg time = 180 total kwh used in 8 weeks veg. It cycles for 20 minutes per hour when lights are on during flower so: @ 4 hrs per day thats 4hrs x 500W = 2000 watts per day. Divided by 1000 x 60 days flower time = 120 total kwh used in 8 weeks veg. Grand total of 2100kwh used in 1 complete grow over 16 weeks. (totaling $210.00 for entire grow) --------------------------------------------------------------------------------------------------------------------------------------------- Grower 2 doesn't veg (uses rooted clones). Grower 2 flowers for 8 weeks. @ 12/12 thats 12hrs x 1000W = 12,000 watts per day. Divided by 1000 x 60 days flower time = 720 total kwh used in 8 weeks flower. Grower 2 uses A/C for 8 wks total. It cycles for 20 minutes per hour when lights are on during flower so: @ 4 hrs per day thats 4hrs x 500W = 2000 watts per day. Divided by 1000 x 60 days flower time = 120 total kwh used in 8 weeks flower. Grand total of 840 kwh used in 1 complete grow over 8 weeks. (totaling $84.00 for entire grow) I get why some would prefer to use gpw, but it just doesnt seem very accurate. I also understand that there are a gazillion variables to this scenario, and that grower 1 will in fact yield some more than grower 2 per harvest -but in twice as much time and almost 3 times the cost. It does'nt seem like a fair assessment to compare the results or skill level from grower 1 and grower 2's same 1000W used? Who would yield more over a 12 month period counting gram per watt USED or KWH?

Yeah you explained it perfectly no doubt. A long time ago I did a quick run through of all my power uses. Rounded up to nearest Dollar Checked draws with kill-a-watt My Flower 500w light costs $20 a month 6" hyper fan 45w draw avg only turned up to 50% 24 hrs day $2 month 4" inline exhaust 25w 24 hr day $2 month Circ fan 25w 24 hr day $2 month AC is a hard variable whole room AC not just in tent. I don't have to use it after mid Oct and won't use it till April. So 6.5 months I use a 750w ac It's turned up to about 40% capacity and it draws less power when compressor isn't Running. So unknown but figure $15 to be fair So spring summer $40 a month for flower tent only $25 month fall and winter Not counting veg tent fans, light's, water pump for DIY aeroponics cloner. Paying 11 cents per kwh this area

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Excellent work on that brother your and your exactly right my best runs under 1000w hps in a 4x4 was 1.65 lb usually avg just over 1.5 so Led really only brought me 8-10 oz more per run. And I owe most of my success to 6 years doing this Nectar for the Gods nutrients and Photosynthesis plus

Gram per Watt still works, you just need to add all the Watts. Fans, timers, AC, humidifier, dehumidifier, CO2 controller etc... i.e. g/W used total was opposed to just GPW the light uses. As noted climate control costs will be different.

So, although the math checks out, this is only 1 part of yur overhead; its one of many things that u subtract from total market value of the product. and it;s incomplete without yeilds.. Say, in 16wks, if #1 pulls more in one run, than #2 w/ gets in w/ 2 runs, the profits could potentially outweigh the $42 difference ($84 x 2) and assuming all other costs are equal, then #1 is has a better margin than #2.. So power use of yur lights and A/C are only part of it.. . If i'm running strains i'm familiar w/, i'll have an idea of the "ounces per sqft" and "grams per m2" that i can get, so i rely on those figure when planning calendars and runs.. For comparisons, ive always tended to rely on Grams per watt per 30 day period. rather than total grams compared to total watts. Having a set mark, (ie 30 days) helps level the playing field and provides for more accurate data.. If I'm running a 6 week afghan and you're running a 12 week haze, it's not accurate to compare weights and watts, as your running yur lights twice as long and spending twice as much timee, energy and money as me, for often times, less yeild. For me the benchmark has always been 0.5 gpw per 30 days.. meaning a 60 day strain ran under a single 1k HID should pull a kilo, or 0.5gpw per 30days, regardless of veg time or number of plants. Now with leds, cobs and cmh, things get cloudy. The distance between the bulb and yur tops is shortened, as are the watts and bulbs' intensity, so im not sure that comparing gpw's of HIDs vs LEDs would be accurate; i think there would be too many variables to account for.. If yur tryn to compare to someone else, then the easier way to tell who is more profitable would be, like how much it costs you total, to get whatever u got, and subtract that from how much u sold it for, Or in the case of personal growers, how much would the fair market value be. Using those figures to compare and contrast to whoever yur tryn to compare yields with would be more accurate, i think..