At Sellpy, we want to inspire everyone to lead sustainable lives. By creating awareness of how our daily decisions affect the climate and by inspiring people to change our behaviour, we want to help more people to consume and live sustainably.
Definition of water savings
Sellpy defines water savings as the amount of water in liters that would be required to produce a new item. By replacing new consumption with second hand you can make a difference by reducing the need to use water to produce new items.
What assumptions has Sellpy made when calculating water savings?
To estimate water savings, we have made some assumptions based on a number of different sources. We collect data about the materials that the items we handle are made up of. Based on this, we have made assumptions about the mixture of materials that each garment consists of in order to obtain an average measure of water savings per garment.
An example of a calculation
About 75% of all sweaters we handle are made up of 100% cotton and the other 25% are made up of 100% wool. By weighting these measurements, we get an average for the textiles that sweaters consist of, i.e. 75% cotton and 25% wool.
We use the product's estimated weight and average water requirement to produce the textiles to estimate the number of litres of water used to produce 1 kg of each garment.
What sources have we used?
We have based our assumptions on a number of different sources:
The Water Footprint, Water in the Supply Chain, Arjen Hoekstra, 2010.
WRAP, Review of Data on Embodied Water in Clothing Summary Report, 2012.
HIGG MSI, Materials Sustainability Index.
CleanMetrics, CarbonScopeData LCI database.
Data from H&M
The Higg MSI and why we use it
The Higg MSI is a tool that can be used as a basis to calculate the environmental impacts of materials in a variety of consumer goods. At Sellpy we use the Higg MSI to obtain emissions factors to calculate the emissions for the production of the raw materials, yarn and fabric. We then apply sustainability data from the H&M to include post production activities. The savings data presented to our customers with regards to CO2 and water savings also include internal data such as weight and material composition.
Although we currently use data from the Higg MSI to highlight the environmental benefits of choosing second hand over newly produced items, we remain mindful that no tool is perfect. Collective and continuous work is needed to advance existing data with better accuracy and detail. We welcome any and all efforts in that direction.