How Much Does Your Website Pollute? Lightweight Code and Sustainability

How a website consumes energy

When someone visits a web page, a chain of operations is triggered involving three elements: the server where the site resides, the network that transports the data, and the user's device that receives and displays it. Each of these steps requires electricity. According to data from the Website Carbon Calculator, the average web page produces about 0.36 grams of CO2 per view. It is a small amount, but it has to be multiplied by the number of visits. A site with 10,000 monthly visits generates around 43 kg of CO2 a year.

The variable that weighs most on this calculation is the weight of the page, that is, the amount of data that has to be transferred with each visit. The heavier a page is, the more data travels, the more energy is consumed along the entire chain.

Why off-the-shelf platforms tend to weigh more

WordPress powers over 40% of websites in the world and is a powerful and accessible platform. It has, however, a structural feature that affects the weight of pages: its plugin-based architecture. A typical WordPress site uses between 20 and 30 active plugins. Each plugin adds code, database queries, CSS and JavaScript files that are loaded with every visit, even when the corresponding features are not used. According to an analysis by Afteractive, around 80% of WordPress sites' performance problems come precisely from plugins.

To this are added page builders such as Elementor, Divi or WPBakery. These tools allow pages to be built without writing code, but they generate more verbose HTML, redundant CSS and additional JavaScript. They are convenient for those who do not program, but they produce pages that can weigh 2-3 MB or more.

Not just WordPress: Shopify, Wix and the other platforms

The problem does not concern WordPress alone. Platforms such as Shopify, Wix and Squarespace show similar dynamics too. Shopify, for example, has made important choices on the hosting front: in 2018 it decommissioned its own data centres to migrate entirely to Google Cloud, which covers 100% of its energy needs with renewable sources (source: CueForGood). This makes the server component cleaner than many traditional hosting providers.

However, the server is only part of the equation. The weight of pages — and therefore the energy consumed by the network and by users' devices — depends on how many apps are installed, on how heavy the themes used are and on how many tracking and marketing scripts are loaded. A Shopify store with 15-20 active apps can easily reach the same weight as a WordPress site loaded with plugins. According to an analysis by Zifera, an e-commerce site with 100,000 monthly views produces around 600 kg of CO2 a year. As reported by Noughts & Ones, the average weight of a web page has quadrupled over the last decade, going from about 500 KB to 2 MB, and images alone account for between 40% and 60% of this weight.

The point, then, is not which off-the-shelf platform you choose. It is that all off-the-shelf platforms share a structural limit: they load generic code designed to cover the widest possible range of use cases, regardless of what the individual site actually needs.

What changes with proprietary code

When a site is developed with code written to measure for the project's specific needs, the result is structurally different from a solution based on off-the-shelf platforms. Proprietary code includes only the features actually needed. There are no plugins loading code that is never used, no JavaScript libraries imported for features that will never be activated, no redundant markup generated by page builders designed to be flexible in any context.

Optimisation happens natively during development. Every image, every script, every resource is sized for the specific purpose, without having to add caching or compression plugins afterwards that introduce further complexity. The practical result is a site that can weigh 5-10 times less than an equivalent built with WordPress and page builders. A homepage of 300 KB instead of 3 MB, with proportionally reduced loading times and a smaller energy footprint.

A numerical comparison

Let us consider two corporate sites with the same appearance and 50,000 monthly visits.

A site built with WordPress and a page builder might have a 2.5 MB homepage and produce about 0.9 g of CO2 per visit, for an annual total of around 540 kg of CO2. An equivalent site built with optimised proprietary code might have a 400 KB homepage and produce about 0.15 g of CO2 per visit, for an annual total of around 90 kg of CO2. The difference is 450 kg of CO2 a year for a single site.

The ESG regulatory framework and digital sustainability

Digital sustainability is progressively entering the scope of European regulations and investor expectations. The European Union's CSRD (Corporate Sustainability Reporting Directive), which came into force in 2023, requires a growing number of companies to report their environmental, social and governance impact. The environmental component concerns climate policies, energy use, emissions and waste management. The most recent regulations require also considering Scope 3 emissions, that is, those generated along the entire value chain, including suppliers and digital services. This means that the company website, hosting and software used are beginning to fall within the scope of reporting.

According to a survey by TechTarget, 94% of IT professionals state that their company would be willing to pay a premium for suppliers with solid sustainability practices. 59% of the investors surveyed by Morgan Stanley in 2025 plan to increase their sustainable investments over the next 12 months. Those who invest in efficient digital solutions can document a concrete commitment to reducing their carbon footprint with measurable data: page weight, estimated energy consumption, choice of green hosting.

Other advantages of lightweight code

Choosing proprietary code for reasons of energy efficiency brings collateral benefits with it.

Performance improves because a lighter site is a faster site. According to WPBeginner, a delay of just one second in loading can reduce conversions by 7% and page views by 11%.

SEO ranking benefits from speed because Google uses Core Web Vitals as a ranking factor, rewarding fast sites in organic visibility.

Security increases because every plugin is a potential attack vector. A site with proprietary code has a reduced attack surface since it depends on fewer external components.

Maintenance becomes simpler because WordPress sites require constant updates of the core, plugins and themes. A site with proprietary code requires intervention only when actually needed.

A126: digital products designed to be lightweight

At A126 we develop digital products with proprietary code. This approach stems from a technical choice that produces concrete results in terms of performance, efficiency and sustainability.

We write code to measure for each project: websites, management systems, e-commerce, applications. Each product includes only the necessary features, without the weight of unused plugins, oversized frameworks or dormant code.

A126 digital products are designed to consume less. Lighter pages mean less data transferred, less work for servers, less electricity consumed with each visit. An A126 site can have a carbon footprint up to 5-6 times lower than an equivalent built with off-the-shelf platforms.

They last longer because they do not depend on third-party plugins that can become obsolete or incompatible. A product that does not have to be rebuilt is a product that does not consume new resources.

They have no waste. We write only the code that is needed. It is the principle of sustainability applied to software: use what is necessary, nothing more.

For companies building an ESG path, choosing A126 means being able to document a digital choice consistent with their sustainability goals, backed by measurable data.

Conclusion

The type of code that powers a website has concrete consequences for its energy consumption. Off-the-shelf platforms with many plugins tend to produce heavier pages. Proprietary code written to measure makes it possible to achieve the same visual result with a fraction of the weight.

As ESG regulations evolve, these considerations are moving from a technical topic to an element of corporate reporting. Knowing how the mechanism works helps in making more informed choices.

A126's digital products are born lightweight, efficient and designed to last. Not because we add something, but because we include only what is needed.

Want to know more about how to build an efficient digital ecosystem? Contact us.