Environment & web

Sustainability comparison CMS vs. HTML website

A comparison of the sustainability of a CMS website and an HTML website starts with one question: how much computing power, data traffic and maintenance does your site require per visit? Together, those factors determine the digital environmental impact — often more than you think.

Here we compare classic CMS sites, such as WordPress or Joomla, with static HTML sites: the server, the network, the visitor's device and the impact of ongoing maintenance.

Request tailored advice To the estimate

CMS site: 10 to 20 kWhPer 100,000 page views, as a rough estimate.
HTML site: 1.5 to 4 kWhFor the same number of views.
Five to ten times lowerAn order of magnitude, not a measurement of your site.

In brief

A static HTML site needs less server work, less data and less computing power from the device per visit. As a result, the energy consumption per page view is usually considerably lower than with a CMS site.

Where does the energy go?

The CO₂ footprint of a website is not only in the data centre. Every page view combines three things. A heavy, slow site consumes more in all three places than a light, fast site — even if the data centre itself uses green electricity.

Work on the server

What the server has to do to build the page and send it.
Bytes over the network

How much data travels from the server to your visitor.
The visitor's device

Processing and drawing the page on a phone or laptop.

CMS site: dynamics come at a price

A CMS often builds pages per request: PHP or similar logic, queries to a database, themes and plug-ins running along. Even with good caching, the server regularly has to get back to work. Every extra plug-in and every admin request costs extra computing power and memory.

That is not “wrong” — it comes with a system that has to remain flexible and editable — but it is structurally heavier than serving a ready-made HTML file.

Want a CMS built with conscious choices? Then take a further look at:

HTML site: built in advance, minimal per click

A static HTML site sits ready as files. The server simply sends them out; there is no database query on every visit and no CMS that has to run along. As a result, energy consumption per page view is usually much lower, especially with well-compressed files and little JavaScript.

That ties in with what we describe on custom HTML web design. How we deal with sustainability ourselves is explained on our sustainability page.

Summary at a glance

The differences between a typical CMS site and a static HTML site, point by point.

A typical CMS site compared with a static HTML site, on four aspects.
Aspect	Typical CMS site	Static HTML site
Server per visit	PHP or another runtime, database, theme and plug-ins; caching helps, but cannot escape the base load	Static files, hardly any computation on the server
Page weight and speed	Varies widely; heavy themes and scripts can make pages bulky	Usually compact and quick to fine-tune; fewer bytes means less energy for network and device
Maintenance	CMS, theme and plug-in updates needed to stay secure and compatible	No CMS update cycle; changes are made deliberately
When does it fit?	Lots of editing, workflows, multilingual content, complex dynamics	Well-ordered sites, a long lifespan, a focus on speed and low impact

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 make that gain, you can read at converting a CMS website to HTML how such a switch works in practice.

Estimate: 100,000 page views

Nobody knows the exact power consumption of one visit to your domain down to the watt — that depends on hosting, cache, page weight and visitor behaviour. Based on common models for data traffic, server load and energy on the device, we can give a rough range. So this is not a measurement in your data centre, but an order of magnitude to show the difference.

WordPress or Joomla 10 to 20 kWh

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

Well-built static HTML site 1.5 to 4 kWh

Compact pages, few requests and no PHP or database per click: for the same 100,000 views you are usually at around 1.5 to 4 kWh — roughly five to ten times lower than the CMS example. That difference lies mainly in less data over the line, less computing 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 with it less pressure on the energy and raw-materials system, even if your host already uses green electricity. HTML-first is therefore a concrete design choice to keep the energy budget per visit small, alongside benefits such as speed and a long lifespan. You will find more about this approach on our page about custom HTML web design.

Tailored advice?

We help you think about whether HTML, a CMS or a combination suits you best — through a sustainability lens too.

WhatsApp Get in touch 073 234 0321 A quick reply, always personal.

Sustainability comparison CMS vs. HTML website

Where does the energy go?

Work on the server

Bytes over the network

The visitor's device