Boohoo, Asos, or TopShop: the brands estimated to generate the most CO₂ from online searches

Special from SaveOnEnergy

With fast fashion largely being driven by the rise in online shopping, energy switching site SaveOnEnergy was keen to investigate the extent to which searches for online fashion retail brands could be harming the environment
With fast fashion largely being driven by the rise in online shopping, energy switching site SaveOnEnergy was keen to investigate the extent to which searches for online fashion retail brands could be harming the environment (illustration: SaveOnEnergy)

Online orders have surged over the last 12 months as customers shop from the comfort of their home – just this week ASOS announced the purchase of four Arcadia group retailers, and with Boohoo having recently purchased Debenhams, both have secured their places as leading UK fashion brands.

With this in mind, energy experts at decided to investigate how much CO2 on average could be generated from website visits to the UK’s most popular online fashion retailers*.

illustration: SaveOnEnergy
illustration: SaveOnEnergy

Least Eco-Friendly Fashion Brands
SaveOnEnergy’s analysis of 25 different retailers reveals which UK fashion retailer is potentially the largest contributor to CO2, by examining how much CO2 is potentially produced from visits to their website.

Next is potentially the largest contributor, with 14,127 kilograms of CO2 produced every month from website visits. This is the equivalent of emissions from driving 35,055 miles – that’s 11 trips as the crow flies from London to New York. One visit to the Next website produces 2.77 grams of carbon dioxide.

In second place is Boohoo, with a potential of 10,815 kg of CO2 emitted each month. This is the equivalent emissions of driving 26,836 miles. That is one trip around the earth’s circumference – and a couple thousand miles more. Just one visit to the Boohoo website generates 7.21 g of CO2 – making it the dirtiest site for a single visit.

In third place is ASOS, with a potential of 3,075 kg of CO2 generated each month on average from website visits. This is the equivalent emissions of driving 7,630 miles – that’s approximately four and a half round trips from Land’s End to John O’Groats. A single visit to the ASOS website generates 1.23 g, placing it amongst the bottom five for emissions from single visits.

PrettyLittleThing is potentially the lowest potential monthly contributor – with only 142 kg of CO2 produced each month from UK wide visits. Despite this, one visit to the PrettyLittleThing website generates 2.34 g of CO2.

Linda Dodge, energy expert at, comments, “Fast fashion is a serious problem for the UK and the rest of the world, and not just from a production perspective. Small emissions from online shopping soon adds up, and this is even more prevalent as consumers shop from the safety of their homes. This study revealed a lot of potential problems with online shopping and highlighted why green energy to power or host retail websites could be beneficial in decreasing emissions.”

The Cities Producing the Most CO2
Having identified the brands that are potentially the most and least eco-friendly, SaveOnEnergy could determine which city potentially contributes the most CO2 from fashion searches, trawling through Google AdWords trend data.

The city potentially emitting the most CO2 from fast-fashion searches is London. With 673,000 monthly average searches for online retailer ASOS alone, it is no surprise that the city of London could produce an average 9,005 kg of CO2 each month from fast fashion online searches. This is the equivalent emissions of flying from London Heathrow to Perth and back – twice.

Aptly named England’s “second city”, Birmingham is in second place with a potential average of 1,785 kg of COproduced every month for fast fashion retail searches. This is 100 kg more than the weight of a Tesla Model X. In third place is Liverpool, with a potential average of 1,151 kg of CO2 produced every month. This is just slightly heavier than the weight of an Alfa Romeo 4C.

Rounding off the top 10 in ninth place is Edinburgh, with a potential of 601 kg produced on average every month from searching online for fast fashion retailers. At number 10 is Belfast, with a potential of 597 kg of CO2 produced every month. These are approximately the same emissions as two round trips from Birmingham (BHX) to Paris (CDG).

For more information and the full results, please see the blog post in full:


* Although Primark is a huge contributor to fast fashion, since they do not have an ecommerce website, they were not included in the study.

** It is assumed that each google search for each respective shop equates to a visit to their website.

  1. looked at the top 20 most populated cities in the United Kingdom.
  2. Search volumes for online fast fashion retailers were extracted for the specific regions using Google AdWords.
  3. These search volumes were then multiplied by the amount of CO2 generated by a single visit to each website, supplied by These numbers have been rounded; for the full decimal, please refer to the data sheet.

UK search volumes (not regional) were procured from Online fast fashion retailers were selected via a combination of popularity and sustainability ratings (provided by

Equivalent weight and CO2 emission data was extracted from a variety of sources, including,,,,, and the Guinness World Records archive. Population statistics were sourced from