Sustainability comparison
CMS vs. HTML website

Where does the energy go?

The CO₂-footprint of a website is not only found in the data centre. Every page view combines: (1) work on the server, (2) bytes across the network, (3) processing and drawing the page on a phone or laptop. A heavy, slow site consumes more in all three places than a light, fast site — even if the data centre itself uses green electricity.

CMS site: dynamics come at a price

A CMS often builds pages per request : PHP or comparable logic, queries to a database, themes and plug-ins that scale along with it. Even with good caching, the origin server periodically has to get to work again. Every extra plug-in and every admin request adds CPU cycles and memory. That is not “wrong” — it comes with a system that has to stay flexible and editable — but it is structurally heavier than serving a ready-made HTML file.

Would you like a CMS with deliberate choices? Then take a look at our pages about WordPress and a Joomla, and at hosting in climate-neutral data centres.

HTML site: built in advance, minimal per click

A static HTML site is ready and waiting as files. The server sends them out as they are; there is no database query on every visit and no CMS runtime that has to run alongside. As a result the energy profile per page view is usually much lower, especially with deliberately compressed assets and little JavaScript. That ties in with what we describe on custom HTML web design and with our sustainability page.

Summary at a glance

No dogma: it is about the right fit

Sometimes a CMS is the only sensible option — for example with frequent publishing by several people, or integrations with other systems. Sometimes HTML is the cleanest and cheapest route for years of stable presentation. We are happy to help work out what suits your situation best; do also read the news item with the same thread running through it. If your site currently runs on a CMS and you want to capture that gain, read at converting a CMS website to HTML how such a switch works in practice.

Estimate: 100,000 page views

Nobody knows the exact electricity consumption of a single visit to your domain down to the watt — that depends on hosting, caching, page weight and visitor behaviour. We can, however, on the basis of common models for data transfer, server load and a energy on the client side, give a rough range for comparable sites. So this is not a measurement in your own data centre, but an order of magnitude to show the difference between a CMS and static HTML.

WordPress or Joomla (a typical business site with a theme, a series of plug-ins or extensions, reasonable caching, on average heavier pages): for 100,000 page views the total energy consumption — server, network and processing on a phone or laptop combined — is often in the region of 10 to 20 kWh. Heavier shops, a lot of tracking or poorly optimised themes can head towards 25 kWh or more for the same number of visits.

A well-built static HTML site (compact pages, few requests, no PHP/database per click): for the same 100,000 views you are usually around 1.5 to 4 kWh — roughly five to ten times lower than the CMS example above. That difference lies mainly in less data over the wire, less CPU time on the server per visit and faster, lighter rendering on the device.

Why this is more sustainable: every kilowatt hour saved means less demand for electricity — and therefore less pressure on the energy and raw materials system, even if your host already uses green electricity. HTML-first is thus a concrete design choice for keeping the energy budget per visit small, alongside benefits such as speed and a long lifespan. You can read more about such an approach on our page about custom HTML web design.