Every page has a cost. Bytes that travel, heat that dissipates. Sustainable web design begins with admitting it, and becomes useful when it gets quantified. This is the exercise for circostudio.io, done against ourselves and published openly.
On the home page, Door 07 states that the technical capacity chosen must be proportional to the value it generates. That's easy to write. It's more useful to demonstrate it on what is in our hands: the site itself.
This site is not our largest compute consumption — that conversation belongs to the cloud architectures we design for clients. But it is the closest measurable unit, the one anyone can audit by opening DevTools. Starting here is the most honest move.
Before presenting our own measurement, a third-party check. The Website Carbon Calculator by Wholegrain Digital — the most widely used public calculator in the field, based on the Sustainable Web Design model — audited circostudio.io and issued the highest rating in its system.
The external audit gives us the verdict. Our internal calculation explains why. We use the same model — Sustainable Web Design v4 — applied to the detail of each page, to understand what weighs and where it can be improved. The model is documented, reproducible, and does not require instrumenting the site with additional telemetry.
A site's sustainability is decided in its first commits, not in an optimization pass at the end. These are the decisions we made on purpose, listed here so they can be discussed.
Each row reflects the actual weight of served HTML (gzip level 9), the sum with fonts loaded on first visit, and the estimate of gCO₂e per average visit (new / returning mix). Fonts are loaded once per session and reused across pages.
| Page | Raw HTML | HTML gzip | + Fonts | gCO₂e / visit |
|---|---|---|---|---|
| index.html | 28.1 KB | 7.5 KB | 192.5 KB | 30.08 mg |
| index-en.html | 27.3 KB | 7.0 KB | 192.1 KB | 30.01 mg |
| laboratorio.html | 37.3 KB | 9.3 KB | 194.3 KB | 30.36 mg |
| servicios-circo-studio.html | 25.0 KB | 6.7 KB | 191.8 KB | 29.96 mg |
| nri-mirada-completa.html | 11.4 KB | 3.2 KB | 188.3 KB | 29.41 mg |
| mapas-simbiosis-digital.html | 30.9 KB | 8.5 KB | 193.5 KB | 30.24 mg |
| mapas-simbiosis-digital-III-IV.html | 39.6 KB | 10.5 KB | 195.6 KB | 30.55 mg |
| Site average · internal estimate | 192.6 KB | 30.09 mg | ||
The standard reference is the HTTP Archive, which reports a median of 2.4 MB per web page in 2024. Applied to the SWD v4 model, that equals roughly 384 mg of CO₂e per visit. The external measurement places us at 50 mg.
Every measurement has a perimeter. What follows distinguishes what is effectively under our control and reflected in the numbers, from what we cannot audit from the client side.
Reducing the site's weight further is possible. The options, in order of impact against effort:
1. Self-host the three font families with strict latin subset, minimal woff2, and font-display: swap. Estimated savings: 30-50 KB per session, plus removal of Google Fonts as an external domain.
2. Re-measure against Website Carbon every time a new page is published. Attach the delta to the release commit. Make measurement part of the workflow, not a yearly exercise.
3. Publish this report in English as well, as editorial localization. Compute governance is a global conversation and worth sustaining in both languages.
None of the three is cosmetic. All are auditable.
50 milligrams per visit is a comfortable number, externally validated, on renewable hosting. But that is not the point. The point is having measured it, having declared the assumptions, having exposed the model's limits, and having left the result open to verification. A company that wants to talk to its clients about compute governance cannot have a heavy 5 MB corporate page loaded with tracking scripts.