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https://usal.es

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
54
GRADE
F
FIX
3
REVIEW
1
PASS
2
INFO
0
Checks
6
2 PASS 1 REVIEW 3 FIX
F
CO2 Per Page Load
Action
3.17g CO2 per view
FIX
3.17g CO2 per view
Critical::
3.17g CO2 per page view
This page transfers 11.2 MB, producing an estimated 3.17g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.59g, network 0.55g, end-user device 2.03g.
Got: 3.17g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 380.2 kg CO2/year
With 10,000 page views per month, this page would generate approximately 380.2 kg of CO2 annually — equivalent to charging 47529 smartphones.

3.17g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 5% of websites

Sustainable Web Design model v4 · Page size: 11.2 MB

Your site
3.17g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.59g
Network
0.55g
End-user device
2.03g
At 10,000 monthly views: Monthly: 31.7 kg · Annual: 380.2 kg · ≈ 47529 smartphone charges
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

F
Carbon Budget
Action
95th percentile
FIX
95th percentile
Warning::
3.17g CO2 — above the median website (0.60g)
Heavier than an estimated 5% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 95th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

3.17g

95th percentile

Cleaner than 5% of websites

✗ Above the median website

vs Median 428% more
vs Target 534% more
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Repeat Visit Weight
100% cached
PASS
100% cached
Info::
100% reduction on repeat visits
Returning visitors download only 23 KB (vs 11457 KB first visit). 156 of 158 resources are served from browser cache, saving 3.16g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 3.17g)
First visit
11457 KB
Repeat visit
23 KB

100% reduction on repeat visits

Saving 3.16g CO2 per returning visitor

156 resources served from cache · 2 resources re-downloaded

A+
Transfer Efficiency
98% efficient
PASS
98% efficient
Info::
Transfer efficiency: 98%
Only 193 KB of potential savings identified. Your page is well-optimized for size.
98% efficient

Total waste: 193 KB (2% of page weight)

Unused JS 193 KB

0.05g unnecessary CO2 per visit

Actual transfer 11457 KB
Theoretical minimum 11264 KB
Potential savings 193 KB (0.05g CO2)

See Deep Analysis sections above for specific optimizations.

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

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