Every one of our products saves an incredible amount of water, CO2 and energy because of the difference between organic and conventional cotton. We estimate each of our products saves:
How do we calculate these numbers? We use the following methods, if you don't like mathematics look away now!
It's widely reported that the average conventional cotton t-shirt requires 2,700 litres of water to make, from the growing of the cotton, through to manufacturing. This figure is quoted by the World Wildlife Foundation, FairTrade Foundation, and National Geographic (there's a great video on this link too).
It's also reported by About Organic Cotton that organic cotton uses 91% less water than conventional cotton. AOC is a great site with loads of information about the benefits of organic cotton!
We interpret an "average" cotton t-shirt to be a Large Unisex T in a standard weight fabric (155gsm) as this is our best selling size of T. This weighs 154g. Therefore we worked out if it takes 2700L to make 154g of cotton, then it would take 17.5L (2700 divided by 154) to make 1g.
We then weighed an average size (medium or large) of each of the other garments on the list, and multiplied the weights by 17.5L to get their conventional cotton water use. We then reduced these numbers by 91% to get their organic cotton water use and quote the difference as the amount of water saved.
In terms of the number of people this amount of water can sustain, the NHS recommends drinking 1.2 litres of water per day per person. We thought that'd leave most people a bit thirsty, so rounded it up to 2 litres per day per person, and the rest is simple maths.
CO2e (CO2 equivalent) Emissions
Our partner factory has reduced the emissions of one conventional cotton T from 7000g to zero by using organic cotton and adapting their manufacturing processes to make both the T and it's transport to the UK climate neutral.
By using the same mathematical method above, if a 154g conventional cotton t-shirt creates 7000g of CO2 emissions, then 1g of cotton creates 45.5g of CO2 emissions (7000 divided by 154).
Again we use the garment weights to work out the CO2 footprint of the equivalent garment in conventional cotton, and in turn how much is saved.
To get the equivalent travelled distance, we found out what the most common car in the UK was (a Ford Fiesta) and in turn what it's emissions of CO2 per kilometer (94g/km) are. Divide the emissions of the garments by 94, and you get the km distance the car would have travelled.
About Organic Cotton state one organic T saves enough energy to keep a 60W lightbulb lit for 33.2 hours, when compared to a conventional cotton one.
60W = 0.06kW, so 0.06kW multiplied by 33.2hrs = 1.992kWh saved
They go on to state here that organic cotton uses 62% less energy, so we can assume that the saving of 1.992kWh is 62% of a conventional cotton T's energy use. If 62% = 1.992kWh, then 100% = 3.2kWh of energy used to make a conventional cotton T.
Again by the same mathematical process above, we can assume the average T weighing 154g therefore requires 3.2kWh of energy to produce, so 1g of conventional cotton requires 0.0207kWh (3.2 divided by 154), and organic requires 62% less.
Use these 1g statistics to calculate the energy use of a garment in both conventional and organic cotton, then subtract one from the other and this gives you the saving.