Sustainable Websites

Sustainable Websites: Impact, Measurability, Implementation

Q: How much CO₂ does a website really cause?

It depends heavily on page size, traffic, hosting, and third-party scripts. As a rough guideline, CO₂ calculators like WebsiteCarbon often cite values in the range of about 1 gram of CO₂ per page view for average pages – but that's a model, not a sensor measurement. It becomes helpful when you compare before and after: Same page, same measurement method, and you see very well whether your measures are effective. If you need an order of magnitude: A sample calculation results in about 211 kg of CO₂ per year for 10,000 visits a month. GreenByDefault

Q: Is it enough if I switch to green hosting?

Switching to a hosting provider with renewable energy is a sensible step, especially if you need an improvement quickly. But it doesn't replace the work on the weight and complexity of the website. Because data transfer and end device computational load remain – and an inefficient page remains inefficient, even if the electricity is green. The combination works best: Green hosting plus reduction of data volume and third parties plus a setup that remains stable in the long run.

Q: Is a fast website automatically sustainable?

Speed is a very good proxy, but not complete proof. A website can be very fast and still run on infrastructure that is not transparent or not renewable. And conversely, a very "green" infrastructure cannot fully compensate for a slower page if unnecessary amounts of data are transmitted. Our approach is therefore multidimensional: We look at Core Web Vitals (UX), page weight (bytes and requests), and CO₂ estimation (model). Only together does a usable picture emerge.

Q: Do I have to forego videos, animations, or strong visuals for sustainability?

No – but you should use them more consciously. Background videos that load automatically are often a classic case of high load with low impact. An explanatory product video or a short team sequence can be meaningful if users actively start it, and it is embedded technically clean. In our projects, we usually look for "same feel, less weight": poster frames instead of autoplay, modern codecs, lazy loading, and clear priorities, on what really needs to be visible.

Q: Which metrics are most important for starting?

If you want to start pragmatically, take three values: transferred weight (MB), number of requests, and LCP from Core Web Vitals. This way, you quickly see if your page "carries too much" and where it gets stuck. After that, you can add a CO₂ estimate with EcoIndex or WebsiteCarbon to make the topic tangible for sustainability communication or internal reports as well.

Q: What are the biggest emission drivers on typical websites?

In many cases, they are large media (hero images, sliders, video), followed by third-party scripts (tracking, consent tools, embedded services), and unnecessarily large amounts of JavaScript. Sometimes there's also a CMS setup that renders dynamically with every call, although the content hardly changes. Third parties, in particular, are tricky because they grow over time. That's why a regular "cleanup day" is worthwhile, where you check what's really needed.

Q: Is WordPress fundamentally "bad" for sustainable websites?

WordPress can be operated sustainably, especially with lean themes, good maintenance, few plugins, and clean image discipline. In practice, however, we often see WordPress setups becoming heavy due to page builders and plugin ballast, and maintenance becomes expensive. Whether WordPress is suitable for you depends on requirements and team. If performance, security, and longevity with high editorial freedom are important, a headless approach or an SSG frontend may be a good alternative – but it doesn't have to be.