A Lighter Website: Cutting Page Weight and Energy Use

Short answer: The most practical way to make a business website more sustainable is to make it lighter: smaller images, no autoplaying video, fewer scripts and fonts, and good caching. Measure page weight with Lighthouse or your browser's developer tools before and after, aiming for Lighthouse's suggested total of under 1,600 KiB per page. Then check whether your host is verified as green with the Green Web Foundation, and ask your provider for evidence if it isn't.

Why page weight is the useful lever

Every page someone loads moves data through networks and devices, and that takes energy. You can't easily measure your own site's carbon footprint precisely, and the calculators online all rest on estimates. What you can measure exactly is how many kilobytes each page sends. Lighter pages also load faster, cost visitors on limited data plans less, and tend to do better in speed metrics. So the work you'd do for sustainability is largely the same work you'd do for performance.

The W3C's Sustainable Web Interest Group has published draft Web Sustainability Guidelines (WSG) that make the same connection. The draft covers design, development, hosting and business practice, and asks teams to set performance and environmental targets and to assess the necessity of third-party services. Treat it as a well-researched checklist, not a standard you must meet; it is still a draft.

Step 1: Audit your pages

Pick five pages: the homepage, your most visited service or product page, a blog post, the contact page and one image-heavy page (gallery, portfolio or menu).

For each one, record:

Total transfer size. In Chrome, open DevTools, go to the Network tab, tick "Disable cache", reload, and read the transferred total at the bottom. Or run Lighthouse and look at the "Avoid enormous network payloads" audit.
Number of requests.
The five biggest files and what they are (image, video, script, font).
Third-party domains loading on the page (analytics, chat, maps, social embeds, booking widgets).

Chrome's Lighthouse documentation gives useful reference points. It recommends keeping total byte size below 1,600 KiB, a target based on what a 3G connection can download while keeping the page usable within about ten seconds. It notes that the median network payload in HTTP Archive data is between 1,700 and 1,900 KiB, and it flags pages over 5,000 KiB.

Step 2: The top eight fixes, roughly in order of impact

On most small business sites, these come up again and again. Start at the top.

1. Resize and compress images

Photos uploaded straight from a phone or a photographer's drive are often several times larger than the space they fill. Resize to the largest size actually displayed, compress, and use modern formats such as WebP or AVIF. The WSG draft's media criteria ask for media to be resized and compressed for different screen sizes and devices.

2. Replace autoplaying background video

A hero video that plays on every visit is often the single heaviest item on the page. The WSG draft recommends disabling autoplay by default and letting users control playback. Use a still image with a play button, or load the video only when someone asks for it.

3. Load below-the-fold media lazily

Images and embeds further down the page should load only when someone scrolls near them. The WSG draft describes using a static placeholder or "facade" for heavy media until the user interacts, which works well for YouTube embeds and maps.

4. Cut third-party scripts

Chat widgets, heatmaps, old ad pixels, social feeds and multiple analytics tools each add code. List them, ask who uses each one, and remove what nobody does. Keep the rest, but load them after the main content where possible.

5. Trim fonts

Each font family, weight and style is a separate download. Use one or two families, only the weights you need, and WOFF2 files. A system font stack for body text removes font downloads entirely.

6. Remove unused plugins and theme features

Page builders and themes often load sliders, animation libraries and icon sets on every page whether used or not. Disabling unused features can shrink scripts and stylesheets noticeably.

7. Turn on caching and compression

Returning visitors shouldn't download the same logo and stylesheet again. Check that your host or CDN sends caching headers and compresses text files. The WSG draft lists caching and compression among the hosting configurations to manage.

8. Remove pages and files nobody needs

Old PDFs, duplicate images in the media library and abandoned landing pages don't affect page weight directly, but they take storage and backups, and they clutter your site. A yearly tidy keeps the whole system lean.

After each round of fixes, rerun the audit on the same five pages and note the new totals. That before-and-after table is your evidence of progress, and it's far more honest than an estimated carbon figure.

Step 3: The hosting question

Where your site runs matters too. The Green Web Foundation's Green Web Check lets you enter a domain and see whether it's served from infrastructure in its Green Web Dataset. According to the foundation, verified green hosting providers have shown evidence, at least yearly, of steps to avoid, reduce or offset the greenhouse gas emissions from the electricity used to provide their services.

If your site doesn't show as green:

Ask your host whether it has applied for verification and what evidence it publishes about its energy.
If you use a CDN, check that provider too; much of your traffic may be served from it.
If you're planning a move anyway, add verified green hosting to your requirements alongside speed, support and backups.

Don't move hosts for this reason alone without checking the rest. A cheap green host with poor performance or support can cost you more than it saves.

FAQ

Should I put a carbon figure on my website?

Only if you can explain where it comes from. Per-page carbon calculators rely on averaged assumptions. Publishing your page weight improvements and hosting choice is more defensible.

Does a dark design save energy?

It can on some screen types, but the effect depends on the device. Page weight and fewer scripts are more reliable improvements for every visitor.

Will a lighter site rank better?

Speed is one of many factors in search, so don't expect a ranking jump. You can expect faster pages, which visitors notice.

If you'd like your five key pages audited and the heaviest items dealt with first, send us the address and we'll report back with the numbers.