Reducing Website Carbon Emissions

Case StudiesD! UK

In an industry first, MEK have documented exactly how they approached and solved this challenge so they can inspire others to do the same and help businesses transition to sustainable digital practices.

Every website on the internet is hosted on a server, and most of the world’s servers are powered by fossil fuels.


Our website has been specifically designed to reduce CO2 emissions and energy consumption associated with accessing and viewing our content.

In an industry first, we documented exactly how we approached and solved this challenge so we can inspire others to do the same and help businesses transition to sustainable digital practices. This open source case study also serves as a roadmap to help designers, studios and agencies create low emission websites as a new service to offer clients looking to reduce their impact.

Because if the internet was a country it would be the world’s fourth biggest polluter.

We need to do better.

Recently we went to a trivia night and one of the questions was ‘What has a bigger carbon footprint: sending 100 emails or driving 1km in a car?’


We answered ‘Driving 1km in a car’, because duh.

Well, we were wrong.

Since learning this startling fact (and losing yet another round of trivia), we wondered what the carbon footprint of our email usage was. We went through all our mail folders and deleted every email we didn’t need or weren’t actively engaged in conversation with.

Before we knew it we’d delved deeper into the world of digital landfill, and like a Choose Your Own Adventure book we had two options:

  • Turn back
  • Do a complete audit

We couldn’t unknow what we learned, so we started researching resources that would help calculate our emissions.

These are our findings:

  • According to the Website Carbon Calculator, our old website produced more carbon than 76.5% of web pages tested. Over one year with ±10,000 monthly page views, it produced:
  • 145.6kg of CO2 equivalent: the same weight as a piano and as much CO2 as boiling water for 19,728 cups of tea
  • The same amount of carbon that 7 trees absorb in one year
  • 329kWh of energy
  • The same amount of electricity to drive an electric car 2,108km

This was incredibly alarming and we knew we had to create a new site asap. We started this process by auditing our old website:

Auditing the code


We revisited the old site’s code and noticed there were too many unnecessary HTML tags that had duplicated over time. This resulted in a high volume of requests sent to the server, impacting the overall site speed and user experience as well as being more energy intensive:

Old website's code
Old website's code


Our new site’s code is clean with no unnecessary or duplicated HTML tags. The site runs faster and smoother.



For the old site’s typography we used Monument Grotesk with different fonts: Regular, Medium, Italic. We’d changed this to the variable version so that one font file contained the same number of stylistic variations, instead of three separate font files for Regular, Medium, Italic. This was to further reduce the number of HTTP requests, but we found it wasn’t enough.

Before: Our website font - Monument Grotesk
Before: Our website font - Monument Grotesk


Primary font: Arial Regular

Secondary font: Courier New Regular

These are both system fonts that are already installed on your device(s), therefore reducing HTTP requests thus energy and emissions. We admit we’re not super thrilled about them, but we can’t in good faith use the fonts we want if we know they’re contributing to higher emissions.

The MEK wordmark appears as text-only on the site instead of a web font or image file. Our logo symbol only appears in the site’s favicon, the little icon on your browser tab.

Emojis and other decorative design elements are not used in order to reduce emissions.



We used a versatile colour system of vibrant and neutral colours throughout the old site. The background was white to showcase our design work with clean, breathable pages that communicated copy efficiently and effectively, however white is the most energy intensive because it comprises all the colours in the colour spectrum.

Old website colour palette
Old website colour palette


  • Dark mode with a surface colour of #121212
  • White text at 87% opacity
  • Disabled text at 38% opacity
  • The contrast ratio of pink is 7:1

All colours, ratios and opacities adhere to Google’s Material Design and pass the Web Content Accessibility Guidelines (WCAG) and Colour Contrast Checker.

The new site is in dark mode which is new for us because we’ve always had light mode websites with beautiful bold colour. From a user experience perspective, dark mode is more visually appealing, and it also reduces eye strain (we haven’t found any scientific data on this so if you have any please let us know).

We used pink because blue is ubiquitous in dark mode palettes and is energy intensive. Pink is one of MEK’s brand colours and is uncommon in brands in our industry and advocacy space, and unique to us. Also, it’s fun.

New website colour palette
New website colour palette



The images on our old site were high resolution JPGs with an average file size of ~700KB. These files impacted speed and significantly increased energy usage and emissions.


Images on our new site are <500KB, optimised and compressed to minimise file handling times. Lazy loading is implemented, which means images only load when you scroll down to them.



The first thing we noticed on our old site that was energy intensive was our homepage, which had a looped slideshow of seven full bleed images ranging from 114KB to 798KB. This drastically increased the site’s speed and load time resulting in high bounce rates. The old site also included various media such as reels, videos and animations, at an average of ~8MB per file.

Old website header (part of a slide show)
Old website header (part of a slide show)


The new site only has static images. They aren’t displayed at full size in order to further minimise loading but you can click on images to enlarge them. Not having big beautiful media and content with a dynamic palette and layout pains us as designers, but we think we did a pretty good job making this site as ‘designery’ as possible within the limited constraints we had to work with.


The new layout is clear and easy to follow, reducing your number of clicks and allowing greater accessibility of content.

Old website layout (part of a slideshow)
Old website layout (part of a slideshow)

Navigation is simplified and clearly described to make information easy to find.

While the site design is restrained and functional, it relies on strong typography to ensure visual interest and user engagement, minimise lengthy copy, and divide sections of content into digestible forms.


After launching the site in March 2023 we ran it through the Website Carbon Calculator again:


  • Dirtier than 76.5% of web pages tested
  • Produced 1.21g of CO2 every time someone visited
  • Produced 145.6kg of CO2 equivalent: the same weight as a piano and as much CO2 as boiling water for 19,728 cups of tea
  • Produced the same amount of carbon that 7 trees absorb in one year
  • Produced the same amount of electricity to drive an electric car 2,108km


  • Cleaner than 57% of web pages tested
  • Produces only 0.42g of CO2 every time someone visits
  • Produces 50.5kg of CO2 equivalent: the same weight as <1⁄3 of a piano and as much CO2 as boiling water for 6,850 cups of tea
  • Produces the same amount of carbon that 3 trees absorb in one year
  • Produces the same amount of electricity to drive an electric car 732km
  • Overall we reduced our website carbon emissions by 67%.

Next Steps


Other things we’ve identified to reduce our emissions are switching to a green host, further reducing file sizes, and planting more trees to offset CO2.

So our next steps are:

  1. Moving to a green web host. By using green hosting our site will emit ~9% less CO2. Green hosts use clean, renewable energy instead of fossil fuel.
  2. MEK plants 10 trees through Carbon Positive Australia for every client we work with. We have increased this to 20 trees to further reduce our carbon emissions.
  3. Using WebP instead of JPG will reduce the size of our images thus emissions. We tested this by converting our JPGs to WebP — there was an average of ~70kb reduction per file, however our current platform doesn’t support WebP file uploads. This will be a priority when we move to a green host. WebP is a file format developed by Google to reduce image file sizes.
  4. We’ll continue looking for more ways to improve this site and reduce our digital impact. If you have any tips or suggestions, or any questions about this case study, please email


Design Declares case studies tell stories of projects that are striving to address the climate crisis through the lens of the 8 Acts of Emergency

Global D! supporters MEK are a Melbourne-based purpose-driven design studio. They re-designed their studio website, reducing it’s carbon emissions by 67%! Here they share their process and findings along the way.