TL;DR: Digital greenwashing is when a business promotes its green credentials while its own website, apps and digital marketing quietly run up a carbon bill nobody mentions. Sky is our worked example: on our 2025 calculation its website produces roughly 284 tonnes of CO2 a year.
The stakes have changed since we first wrote this. Since 6 April 2025 the CMA can fine UK businesses directly for misleading green claims, and stricter EU rules for anyone selling to EU consumers took effect on 27 September 2026.
Below: what digital greenwashing is, the Sky numbers with the working shown, what UK and EU law now says, how to measure a site honestly, and how to make green claims that hold up.
Key takeaways
- QED Web Design estimated Sky’s website at 1.53g of CO2 per page load, which across 72.72 million visits a year and 2.55 pages per visit comes to roughly 284 tonnes of CO2 annually.
- Since 6 April 2025, the Competition and Markets Authority can fine businesses up to £300,000 or 10% of global turnover, whichever is higher, for misleading consumer claims, green claims included.
- From 27 September 2026, generic claims such as “eco-friendly” are banned in the EU unless backed by recognised excellent environmental performance, and the rules apply to UK traders selling to EU consumers.
- Website carbon figures are modelled estimates, not measurements: version 4 of the Sustainable Web Design Model gives results around two-thirds lower than version 3 for the same page.
- A heavy website is not greenwashing on its own; the legal risk starts when a business makes green claims that leave its digital footprint out of the picture.
Digital greenwashing is the gap between what a company says about the planet and what its own website does to it. We are QED Web Design, a sustainable WordPress and Elementor studio in South Brent, South Devon, and we measure websites for a living, so that gap is hard for us to ignore.
We first wrote this post in September 2025, after Sky shared a LinkedIn post of its sustainability team talking up eco-friendly products, recycling emojis and all. So we ran Sky’s own website through the numbers. They were not pretty.
A year on, the ground has shifted. UK regulators can now fine directly for misleading green claims, and new EU rules arrived in September 2026. Here is the refreshed version: our original Sky calculation with the working shown, what the law now says, and how to keep your own claims honest. If you are planning a new site, our sustainable website design packages are built on the same principles.
What is digital greenwashing?
Digital greenwashing is making environmental claims about a business while leaving out the environmental cost of its digital operations: websites, apps, streaming, ad tech and data. It is a branch of ordinary greenwashing, meaning a green claim that gives a false or incomplete impression.
Every page view has a cost. A visitor’s browser pulls data from a server in a data centre, across networks and onto a device, and every step draws electricity. A heavy web page is like leaving the engine running in the car park: nobody sees the fumes, but the fuel still burns.
The Competition and Markets Authority (CMA), the UK’s consumer protection regulator, says in its Green Claims Code (CMA, 2021) that claims must consider the full life cycle of a product or service. A company that celebrates recyclable packaging while ignoring a website visited tens of millions of times a year is, at best, telling half the story. For the wider picture of what good looks like, see our guide to what sustainable web design actually means.
The clearest way to see the gap is with a real example, which is where Sky comes in.
How much carbon does Sky’s website produce?
On QED’s 2025 calculation, Sky’s website produces roughly 284 tonnes of CO2 a year, about the same as 134 average cars each driving 10,000 miles. We used three inputs, all public, so anyone can check the sums.
- Traffic: SimilarWeb put Sky’s website at 72.72 million visits a year.
- Depth: SimilarWeb recorded an average of 2.55 pages per visit.
- Carbon per page: Ecograder estimated 1.53g of CO2 per page load.
For scale, our client Ancient Shepherds by Mark Poynton, a photography-led restaurant site, came in at 0.23g of CO2 per visit on Ecograder in our 2026 study. Sky’s per-page figure is more than six times higher. The two were tested at different times, so treat that as an indication rather than a league table.
Sky is not unusual. HTTP Archive’s 2025 Web Almanac found the median mobile home page weighed 2,362 KB in July 2025, up from 845 KB in 2015 (as reported by Search Engine Journal, 2025). The whole web is getting heavier, and big corporate sites, packed with video, tracking scripts and animation, sit at the heavy end.
We are not saying the website is Sky’s biggest environmental problem. Next to studios, set-top boxes and supply chains, it almost certainly is not. The point is that it was left out of the story entirely, which raises an obvious question.
Why do big sustainability pledges miss the website?
Corporate sustainability plans tend to chase the emissions that are easy to see and easy to report: buildings, fleets, factories and packaging. Websites fall between departments. Marketing owns them, IT builds them, and nobody measures them.
Sky’s own environment page, checked on 28 October 2026, lists 100% renewable electricity for its UK and Ireland operations, an electric vehicle fleet, recyclable packaging and its Elstree film studios. Those are Sky’s own claims. The page does not mention its website, apps or streaming services at all.
The headline target has also changed. In February 2020 Sky announced it would be net zero carbon by 2030 (Sky, 2020). Its environment page now describes a science-based target to halve absolute Scope 1, 2 and 3 emissions by 2030 from a 2018 baseline, with Sky UK Limited committed to net zero by 2050 (Sky, 2026). Scope 1, 2 and 3 are the standard buckets for a company’s emissions: its own fuel, the energy it buys, and everything else in its value chain.
The same blind spot turns up well beyond big media. In our Michelin Green Star website study, restaurants recognised for sustainability averaged 1.92g of CO2 per visit against 2.29g for a control group, yet around 84% of the Green Star sites still scored an E grade on Ecograder. Sustainable in the kitchen does not mean sustainable in the browser.
Renewable electricity in the office does not make a 5MB homepage light. That is the sustainability paradox in one sentence, and it is why the law now matters as much as the maths.
Is digital greenwashing illegal in the UK?
Misleading green claims are illegal in the UK wherever they appear, on packaging, in an advert or on a website. Since 6 April 2025 the CMA can fine businesses directly for them under the Digital Markets, Competition and Consumers Act 2024 (DMCC Act), without going to court first (Fieldfisher, 2025).
The ceiling is £300,000 or 10% of global turnover, whichever is higher (Ashurst, 2026). Before April 2025 the CMA largely had to take businesses to court or accept voluntary undertakings, so the new powers are a real step up.
The CMA has also widened who carries the risk. Its guidance Making green claims: getting it right, across the supply chain, published on 22 January 2026, makes clear that a business repeating or passing on someone else’s environmental claim can share liability for it (CMA, 2026). A retailer cannot hide behind a supplier’s leaf logo.
The scale of online greenwashing is not new, and neither is the gap it exploits. A 2021 international sweep of around 500 websites, co-led by the CMA, found that 40% of green claims made online could be misleading consumers (CMA, 2021).
UK businesses that sell into the EU face stricter rules still. From 27 September 2026, Directive (EU) 2024/825, known as the Empowering Consumers for the Green Transition Directive, bans generic claims such as “eco-friendly” or “green” unless the trader can show recognised excellent environmental performance (PwC Italy, 2026). There is no transition period for existing claims (Latham & Watkins, 2026). It also bans claims that a product has a neutral or reduced impact because of offsetting, and it applies to anyone selling to EU consumers, wherever they are based (TLT, 2026).
| Green claims rules | UK consumers | EU consumers |
|---|---|---|
| Main rules | DMCC Act 2024, with the CMA Green Claims Code (2021) as guidance | Directive (EU) 2024/825 (Empowering Consumers for the Green Transition) |
| In force from | CMA direct fines since 6 April 2025 | 27 September 2026, no transition period |
| Who it covers | Claims made to UK consumers | Traders selling to EU consumers, wherever they are based |
| Generic "eco-friendly" claims | Risky unless clear and evidenced | Banned without proof of excellent performance |
| "Carbon neutral" via offsetting | Must be clear and not mislead | Banned for products |
| Maximum penalty | £300,000 or 10% of global turnover, whichever is higher | Set by each member state |
| Claims checked before use? | No | No, the separate Green Claims Directive has stalled |
One thing has not happened. The separate EU Green Claims Directive, which would have required claims to be verified before use, stalled when the European Commission announced its intention to withdraw it on 20 June 2025 (Latham & Watkins, 2025). Anyone waiting for that law before tidying up their claims has missed the deadline that actually applies.
For a small business, the practical position is simple. A modest site that makes no environmental claims is not the target here. A business that writes “eco-friendly” across its homepage with nothing behind it is making exactly the kind of vague claim the Code warns about. QED Web Design is not a law firm, so take legal advice if you sell heavily into the EU. Every one of these rules comes back to evidence, which means you need a number you can defend.
How do you measure a website’s carbon footprint honestly?
You estimate it rather than measure it, using free tools such as Ecograder or the Website Carbon Calculator, which convert the data a page transfers into an emissions figure. The number is a model, so how you use it matters as much as the number itself.
Most of these tools run on the Sustainable Web Design Model (SWDM), an open method maintained by Wholegrain Digital, Mightybytes, the Green Web Foundation and others. Version 4 splits energy use across data centres, networks and user devices, and the model’s own authors say its broad boundaries are likely to overestimate actual emissions (Sustainable Web Design, 2024).
The commonly repeated idea is that a website carbon figure is a hard fact. It is not. According to the Green Web Foundation, one of the model’s authors, version 4 produces estimates on average two-thirds lower than version 3 for the same page (Green Web Foundation, 2024). Same website, different model, very different number.
That cuts both ways, including for our own Sky figure. If the tool we used in 2025 was still on the older model, a re-test today could come in lower without Sky changing a thing. Honest reporting means saying which tool, which page and which date, every time.
Measured that way, the numbers become the best defence against digital greenwashing. When QED Web Design rebuilt our own site, the Website Carbon Calculator reading fell from 0.24g to 0.04g of CO2 per page view. A claim like that, with a tool and a before-and-after, is the kind a regulator or a sceptical customer can actually check.
How can a business avoid digital greenwashing?
Avoid digital greenwashing by making claims you can measure, saying exactly which part of the business they cover, and fixing your website before you advertise its credentials. In practice that is two jobs: clean up the site, then clean up the wording.
For the site, we use the same four-step sequence we published in our Michelin Green Star study. It is boring on purpose.
- Measure your homepage and one key journey, such as booking or checkout, and note the tool and date.
- Fix images first with WebP or AVIF and sensible dimensions, because images are usually the biggest chunk of waste.
- Cut third-party scripts down to the ones you can defend commercially.
- Re-test quarterly, so weight creeping back after launch gets caught early.
Green hosting helps, but it does not fix bloat. Renewable-powered hosting reduces the data centre share of a page’s footprint; it does nothing about the network and device energy a heavy page burns on its way to a visitor’s phone. If you want the bigger context on servers, our piece on the myths around AI data centre pollution covers it.
For the wording, swap adjectives for facts:
- “0.23g of CO2 per page view (Ecograder, tested in 2026)” beats “eco-friendly website”.
- Say what a claim covers. If you mean your packaging, say packaging, not “we’re a sustainable business”.
- Be very careful with offsetting. If a claim relies on it, say so plainly, and do not use it for products sold into the EU.
- Keep the evidence on file before the claim goes live, not after someone asks.
No tool can certify a website as carbon-free. A lean site is lower-impact, not zero-impact, so “carbon neutral website” is a claim we would steer clear of altogether.
What should a UK business do next?
Check that your website matches what you say about the planet, because regulators and customers now can and do check. Measure it, fix the obvious waste, and only then talk about it, with the numbers.
The answer to digital greenwashing is not to stop talking about sustainability. Environmental communication drives real change. The answer is to make the channel match the message: a transparent “here is our footprint, and here is how we are cutting it” beats a glossy pledge every time.
If you want to know where your own site stands, ask QED Web Design for a free website carbon check. We will give you the figure, the tool we used, and the quick wins.
Sources
- Competition and Markets Authority, Green claims code: making environmental claims, 2021.
- Competition and Markets Authority, Making green claims: getting it right, across the supply chain, 22 January 2026.
- Competition and Markets Authority, Global sweep finds 40% of firms’ green claims could be misleading, 2021.
- Ashurst, Greenwatch: greenwashing in the spotlight, regulatory risks across the supply chain, 2026.
- Fieldfisher, Greenwashing under scrutiny: the CMA’s new powers to tackle misleading environmental claims, 2025.
- Latham & Watkins, EU Empowering Consumers Directive: new rules on green claims apply from 27 September 2026, 2026.
- PwC Italy, Greenwashing, the European crackdown: from 27 September, generic claims and non-certified labels are banned, 2026.
- TLT, The EU’s Empowering Consumers for the Green Transition Directive: what your business needs to do before September 2026, 2026.
- Latham & Watkins, European Commission announces intention to withdraw EU Green Claims Directive proposal, 2025.
- Sky Group, Environment, accessed 28 October 2026 (vendor source).
- Sky Group, Sky commits to become net zero carbon by 2030, 2020 (vendor source).
- Sky, LinkedIn post that prompted this analysis, 2025 (vendor source).
- HTTP Archive, Web Almanac 2025, page weight data, as reported by Search Engine Journal: Google: pages are getting larger and it still matters, 2025.
- Sustainable Web Design, Estimating digital emissions (Sustainable Web Design Model, version 4), 2024.
- Green Web Foundation, Release guide: CO2.js v0.16, 2024 (co-author of the model it describes).
