Skip to content
https://epfl.ch

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
75
GRADE
C
FIX
1
REVIEW
3
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 3 REVIEW 1 FIX
D
Green Hosting
Action
Not green
FIX
Not green
Info::
No confirmed renewable energy commitment detected
Consider providers like Cloudflare, Google Cloud, or Vercel that match 100% of their energy use with renewables.
Info::
Green hosting status based on known provider commitments
Green hosting detection uses a curated database of provider renewable energy commitments. This is not a real-time verification. For authoritative checks, visit thegreenwebfoundation.org.
Green HostingNot Green Hosted
Hosting Apache HTTP Server✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

B
Carbon Budget
38th percentile
REVIEW
38th percentile
Info::
0.48g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 62% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 38th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.48g

38th percentile

Cleaner than 62% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 19% cleaner ✓
vs Target 3% cleaner ✓
B
Transfer Efficiency
86% efficient
REVIEW
86% efficient
Info::
Transfer efficiency: 86%
An estimated 248 KB (14%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 248 KB of unused JavaScript. This wasted data produces 0.07g of unnecessary CO2 per page view.
86% efficient

Total waste: 248 KB (14% of page weight)

Unused JS 248 KB

0.07g unnecessary CO2 per visit

Actual transfer 1751 KB
Theoretical minimum 1503 KB
Potential savings 248 KB (0.07g CO2)

See Deep Analysis sections above for specific optimizations.

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A
CO2 Per Page Load
0.48g CO2 per view
PASS
0.48g CO2 per view
Info::
0.48g CO2 per page view
This page transfers 1.7 MB, producing an estimated 0.48g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.09g, network 0.08g, end-user device 0.31g.
Got: 0.48g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 58.1 kg CO2/year
With 10,000 page views per month, this page would generate approximately 58.1 kg of CO2 annually — equivalent to charging 7266 smartphones.

0.48g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 62% of websites

Sustainable Web Design model v4 · Page size: 1.7 MB

Your site
0.48g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.09g
Network
0.08g
End-user device
0.31g
At 10,000 monthly views: Monthly: 4.8 kg · Annual: 58.1 kg · ≈ 7266 smartphone charges
A+
Repeat Visit Weight
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 18 KB (vs 1751 KB first visit). 50 of 51 resources are served from browser cache, saving 0.48g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.48g)
First visit
1751 KB
Repeat visit
18 KB

99% reduction on repeat visits

Saving 0.48g CO2 per returning visitor

50 resources served from cache · 1 resources re-downloaded

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback