How to calculate the electricity cost of a grow.

[ninja bud]

I thought I would start a thread to show all the indoor growers how to calculate the amount of money their grow is costing to run. When I started growing a few years ago I did a lot of research on the cost of running my grows and have a way to calculate the cost to show you.

1. Add up the total watts that all of your equipment is rated at. Lets say for arguments sake you have a room with a 400 watt hps, a couple of fans at 40 watts, a dehumidifier at 20 watts etc. This gives you a total wattage of 460 watts in your room.

2. Now you must multiply this wattage figure by the amount of hours you are running the equipment in the room. Lets say you are in vegging stage at 18/6. Multiply 460x18 to give you the amount of kilowatt hours you are using each day.
This gives you 8280 kw/hrs.

3. Now to get the amount of units of electricity you are using simply divide 8280 by 1000 and this gives you your unit usage per day. In this case it is 8.28 units.

4. Go to your bill and get the cost per unit of electricity. For arguments sake I am going to say the cost is 15 cent per unit.
Multiply 8.28 units x .15 and this gives you a total of 1.24 euros per day. Multiply this by the days in the month and there you have the cost of you grow per month.

This has been simplified a bit because the lights may be on 18 hours but fans and other equipment may be running for longer than that but you can still use the above info to work out its cost.

Hope this helps anyone that would like to know the cost of their grow.

 

[GrowNut]

thanks, great write up

 

[Lonely Pint]

OK Then

OK Then

I've been working this out myself just recently and was quite amazed at the results. Let's see if I can get it right;

1. Electricity- First 3 weeks 96 watt T5 x 24/7 @ £0.15 per K/WH
= £7.26
Then 14 weeks 96 watt T5 24x7 @ £0.15 per K'WH= £33.87
Plus 14 weeks at 1200 watts 12x7 @ £0.15 per K'WH= £212

2. Substrate- 5x11 Litres of coco @ £6.00 per 70 Litre block= £6.00

3. Food- B.A.C coco nutrients- Bought 20 litres of A and 20 litres of B for £20.00 Application 2mls per litre A and B works out at 10 000 litres @EC .8. The strain is Nevilles Haze so thats plenty good enough.
80 litre rez £0.02 per litre =£0.16 per fill. For the sake of argument, a plant say drinks 240 litres in 120 day life. Thats £0.48 per plant@ 5 plants = £2.40.

4. Harvest- Five plants, all from seed so times ranged from 77 days to 120.
First plant came in at 140 grms @ 77 days
Second plant came in at 160 grms @ 98 days
Third plant came in at 250 grms @ 120 days
Fouth plant came in at 280 grms @ 120 days
Fifth plant came in at 330 grms @ 120 days
So, thats an actual harvest of 1160 grammes, plus I got pickings for a good 6 weeks too. Also I think it's important to include that as plants were harvested I was able to put a new one in it's place. Over the 120 day cycle, that allowed me an extra plants worth of photons, exactly 17 weeks. The average weight of one of those plants is 280 grms. So actual 1160, projected is 1440= 51 ounces in old money.
Thats the 330 grm one

So that's £ 224.27 for 1160 grammes =£0.19 per gramme actual
£0.15 projected.
Hope I got that right, it's late and I'm burnt out. Just goes to show what's possible without all the hydro hype burning our plants and our pockets, lol.

Cheers Lonely