GPW (Grams Per Watt) standing calculation method

BM9AGS

Well-Known Member
Update

The general consensus for what we see as GPW is your grams of trimmed product divided by your grow lights watt pull.

Yes there are many better ways but this is the general system. G/W

What is the calculation method for the sum of ones GPW?

lights on, lights only electricity usage divided by grams of trimmed flowers

Lights on, all electricity usage inc. Room conditioners I.e. Fans and ac, hum...divided by grams of trimmed flowers

Sum of electricity used through whole grow....which is too much math

I couldn't find any constant methods from my googlefu

Thanks
 
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ISK

Well-Known Member
What is the calculation method for the sum of ones GPW?

lights on, lights only electricity usage divided by grams of trimmed flowers

Lights on, all electricity usage inc. Room conditioners I.e. Fans and ac, hum...divided by grams of trimmed flowers

Sum of electricity used through whole grow....which is too much math

I couldn't find any constant methods from my googlefu

Thanks
example if a 600 watt light produce 600 grams of dried pot, that would be 1 gram/watt

BTW: the whole g/w is a bit of a farce, maybe that's why you didn't get much on google
 

BM9AGS

Well-Known Member
example if a 600 watt light produce 600 grams of dried pot, that would be 1 gram/watt

BTW: the whole g/w is a bit of a farce, maybe that's why you didn't get much on google
Yes this is what I gathered.

Why is your opinion of it a farce? Because of too many variables? Intermittently run AC units are not calculated. Stuff like that?

Or because mainly quality is not measured by quantity. And how it's very strain dependent
 

ISK

Well-Known Member
all of the above...also depends on what kind of light, as a 250 w HPS will likely outperform 250 watts of CFL

lots of factors to determine the final yield, best to grow healthy plants and make the best of what you get
 

New Age United

Well-Known Member
What is the calculation method for the sum of ones GPW?

lights on, lights only electricity usage divided by grams of trimmed flowers

Lights on, all electricity usage inc. Room conditioners I.e. Fans and ac, hum...divided by grams of trimmed flowers

Sum of electricity used through whole grow....which is too much math

I couldn't find any constant methods from my googlefu

Thanks
Lights only I'm producing up to a lb for a 600w light so .75g per watt but I figured with my heat and ac I'm pulling nearly double that at a total of 600w per hour Avg. Between 8 weeks of 18-6 and 9 weeks of 12-12 it would equal out to .75g per watt each hour avg.
 

BM9AGS

Well-Known Member
Lights only I'm producing up to a lb for a 600w light so .75g per watt but I figured with my heat and ac I'm pulling nearly double that at a total of 600w per hour Avg. Between 8 weeks of 18-6 and 9 weeks of 12-12 it would equal out to .75g per watt each hour avg.
You're confusing me here.
If you're running a 600w light and watt used in an HR for room conditioning is ~600w then you're using ~ 1200watts. As a appliance watt rating is for an hrs of use or 3600 seconds.

So your True lights on grow room conditioning GPW is 1200w/grams

.375 GPW

No?
 

New Age United

Well-Known Member
You're confusing me here.
If you're running a 600w light and watt used in an HR for room conditioning is ~600w then you're using ~ 1200watts. As a appliance watt rating is for an hrs of use or 3600 seconds.

So your True lights on grow room conditioning GPW is 1200w/grams

.375 GPW

No?
I run a 600w light for 18 hrs a day during veg 8 weeks and 12 hrs a day during flower, So that's an avg of 375 watts per hour plus I timed my heater and my ac and figured from the time they spend on and the watts they draw, that it works out to approx 600w per hour every hour of the day all year long.
 

BM9AGS

Well-Known Member
all of the above...also depends on what kind of light, as a 250 w HPS will likely outperform 250 watts of CFL

lots of factors to determine the final yield, best to grow healthy plants and make the best of what you get
I'm more wondering why you believe it's a farce. If we have a standard calculating method then everything will be scailing appropriately scaling.

i.e. An LED will have a higher total grow room GPW as its more effienct and needs less/no AC or cooling needs.

If we establish a constant of average lights on wattage usage over an hr then the only variables are now the growers abilities/control/plant genetics

yes?

My search was to find a constant used.
As my idea is that it SHOULD be watts used on during lights on + total grow room watts used in an hour.

So if you're running a 50watt inline fan 24/7 and have an AC unit that needs 300 watts but it's only on for ~30 min per hour all with a 600 watt HID then your power usage per hr while lights on would be 150w + 50 w + 600w so 800 watts. Which means for 1GPW effiency you'd need 800 watts.
 

BM9AGS

Well-Known Member
I run a 600w light for 18 hrs a day during veg 8 weeks and 12 hrs a day during flower, So that's an avg of 375 watts per hour plus I timed my heater and my ac and figured from the time they spend on and the watts they draw, that it works out to approx 600w per hour every hour of the day all year long.
Ahh I see.
Yes this is why I can't find a GPW system in place as everyone interprets it differently.

If no ones found or knows of an I place standard can we establish one on this forum please?

I think it needs to be simple enough for someone of moderate intelligence to calculate in their head.

I.e. My grow room uses 450 watts lights on with fans
My filter and humidity control runs 15 min an hr and is rated at 50 watts

I produce 300 grams

So 50/4 is 12.5 because my in line fan runs for 1/4th an hr

So 450+12.5 is 462.5

Then for GPW divide grams by watts
And that gives me .75 GPW.

That's pretty simple and straight forward.

Those wanting to feel better can say I run 12/12 so I'm 1.5 but the purpose of GPW calculations is to check your effiency of grow room and strains therefore leaving out grow room conditioning like AC or heating or dehumidifier is not accurate.
 

BM9AGS

Well-Known Member
it's a farce because people get way too hung up over it.....point in case
To any one interested in business it would be something to pay attention too.

If you grew in a warehouse in Hawaii at .24c a KW and we're paying 3k a month to make $20k of product that's something that must be considered.

If you're in Colorado and had a green house you'd need to consider the winter heating and summer cooling

So I'm looking for something we can all use that's not too complicated and stands across the board.
 

New Age United

Well-Known Member
Ahh I see.
Yes this is why I can't find a GPW system in place as everyone interprets it differently.

If no ones found or knows of an I place standard can we establish one on this forum please?

I think it needs to be simple enough for someone of moderate intelligence to calculate in their head.

I.e. My grow room uses 450 watts lights on with fans
My filter and humidity control runs 15 min an hr and is rated at 50 watts

I produce 300 grams

So 50/4 is 12.5 because my in line fan runs for 1/4th an hr

So 450+12.5 is 462.5

Then for GPW divide grams by watts
And that gives me .75 GPW.

That's pretty simple and straight forward.

Those wanting to feel better can say I run 12/12 so I'm 1.5 but the purpose of GPW calculations is to check your effiency of grow room and strains therefore leaving out grow room conditioning like AC or heating or dehumidifier is not accurate.
OK I'm going by memory here so I may err. During lights on I'm drawing 600w plus my ac runs for a total of 11 mins an HR and I believe it's drawing 1200w plus in the winter time my heater is running as much as 20 mins out of the hr and it's drawing 1200w. Now when the lights are on my heater runs less and when the lights are off my ac runs less so these are all factors, but I am just one month shy of calculating the Avg of the whole shebang for a whole year every hour of the day which imo is the most accurate way of telling power consumption to yield ratio.
 

Budley Doright

Well-Known Member
Shouldnt it be grams per total KWH if you really were wanting to know the actual per watt used to produce it from start to finish. But then, if you produce 2 grams per watt and its shit big bud, well then does it really matter other than you just wasted a whole crap load of watts, lol. Hard for me to figure it out as I never weigh it, just depresses me reading the wild monster yields some report here.
 

BM9AGS

Well-Known Member
OK I'm going by memory here so I may err. During lights on I'm drawing 600w plus my ac runs for a total of 11 mins an HR and I believe it's drawing 1200w plus in the winter time my heater is running as much as 20 mins out of the hr and it's drawing 1200w. Now when the lights are on my heater runs less and when the lights are off my ac runs less so these are all factors, but I am just one month shy of calculating the Avg of the whole shebang for a whole year every hour of the day which imo is the most accurate way of telling power consumption to yield ratio.
I'm glad you're doing that. I'd love to know your years expenditure in electricity.
 

BM9AGS

Well-Known Member
Shouldnt it be grams per total KWH if you really were wanting to know the actual per watt used to produce it from start to finish. But then, if you produce 2 grams per watt and its shit big bud, well then does it really matter other than you just wasted a whole crap load of watts, lol. Hard for me to figure it out as I never weigh it, just depresses me reading the wild monster yields some report here.
Lol yeah there's some monster growers here.

If you used KWH you're simply moving the decimal point bro.....
Watt rating of appliances are in WH so my oven is rated at 1500 watts so KWH is simply 1.5KWH
 

redi jedi

Well-Known Member
I agree there should be a time/energy factor in the equation.

GPW/kWh used.

This would help factor in veg time. IMO anyways.
 

BM9AGS

Well-Known Member
I agree there should be a time/energy factor in the equation.

GPW/kWh used.

This would help factor in veg time. IMO anyways.
I do agree. We could have 2 systems
True GPW. That's the whole shebang.
This would give 12/12 guys from seed something to play with
And
High output *hour GPW. Which would be total grow room wattage of a lights on hour.
I add asterisks to hour because an ac unit maynot run the full 60min of an HR so it's extremely unfair to calculate for an hours use. Also, I suspect a lot of folks don't know the rating in watts of an appliance(light, humidifier and the like) is for an hrs usage


This would be another great tool for helping people purchase lights.
Say a list
Guys averaging .35 GPW for the eBay special "1kw HPS killer 50watt t5 light"
Guys averaging 1.3 GPW with Cree cob CXB 3590 driven at 50%
Guys averaging .5 GPW on HID.

This is why I want an establish system
 
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Budley Doright

Well-Known Member
Well really the only true way to tell is to monitor each circuit running the room with a watt meter. Heat, cooling, chiller, etc. but at the end of the day IMO it would really only be needed for cost versus profit to setup margins in product pricing, is it really that important otherwise?
 

Budley Doright

Well-Known Member
If I grow enough to have a jar or two left when the next run comes in I'm happy. FYI I'm not happy a lot these days lol.
 
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