“We’re carbon neutral.” “We run on one hundred per cent renewable energy.” “We’re eco-friendly by design.”
Three claims, appearing on agency websites everywhere, and the third one means nothing at all. The first two might mean something specific or might mean an offset purchase and a hosting invoice.
The distinction between sustainable agency vs greenwashing is not about intent. Most agencies making vague claims are not trying to deceive anybody; they have adopted the vocabulary without the measurement behind it. The problem is that you inherit the exposure.
Sustainable Agency vs Greenwashing: Spot the Difference
The patterns worth recognising
- Claims about the agency, offered as claims about your website. Their office electricity, their travel policy and their offsetting are operational facts. None of them affects what your pages send.
- Offsets presented as reduction. Planting trees is a payment made elsewhere. It does not reduce transferred bytes, device processing or hosting draw. A heavy site with offsets is a heavy site.
- Absolute language without measurement. “Eco-friendly”, “green by design”, “sustainable build”. If no figure follows, no figure exists.
- Badges without documentation. A logo indicating renewable hosting reflects a claim made by the host. Ask what it covers and whether they can show you.
- Precise carbon figures with no method. A number quoted without the tool, conditions and date suggests either misunderstanding of the modelling or selective presentation of it.
- Certifications that do not exist. There is no recognised certification for sustainable web design. Anything presented as one deserves a direct question about who issues it and what it assesses.
Why the risk lands on you
This is the part that gets underplayed, and it is the reason to care beyond simply not being misled.
If an agency supplies you with “carbon neutral website” wording and you publish it, the claim is yours. Environmental claims must be accurate and substantiated, and the Competition and Markets Authority’s Green Claims Code sets out what that requires of the business making them.
The agency has moved on. You are the one with the claim on your website, in your tender responses and in your ESG reporting.
That asymmetry is why vague sustainability marketing is worth refusing even when it would be convenient to accept.
What a credible answer sounds like
A baseline: page weight, request count and Core Web Vitals recorded before work started, under stated conditions.
A named measurement method: which carbon estimation tool, tested how, with the acknowledgement that these produce modelled estimates rather than measurements and that different tools disagree.
A measured reduction: the same pages, the same conditions, afterwards.
Where performance and environmental impact both apply, a credible agency describes them as the same delivery lever, and says unprompted that reducing unnecessary data transfer and processing supports a faster experience while lowering estimated digital carbon, with the environmental figures acknowledged as modelled rather than directly measured.
And a clear statement of what they cannot promise. Nobody can guarantee rankings, conversion uplift or a precise carbon figure.
The test that takes one minute
Run their own website through a page weight test while you are talking to them.
An agency selling lightweight builds should have a lightweight build. It is difficult to argue with, requires no technical knowledge, and settles more than an hour of conversation.
Then do the same to two sites in their portfolio. A studio whose own pages are light but whose client work is heavy has a process problem: the standards apply to their marketing and not to what they ship.
When the answer is genuinely uncertain
Not every gap is greenwashing, and treating it that way will cost you good suppliers.
An agency that says it has not measured previous projects but is willing to baseline yours is being honest. One that admits its carbon figures come from a single free tool and describes the limitations is more trustworthy than one presenting a precise number with no context.
The distinction is between not knowing and pretending to know. The first is fixable within a project. The second tells you how every subsequent claim should be read.
Our website sustainability audits lead with the baseline, and we would expect this test to be run on us.