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https://fes.de

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
84
GRADE
B
FIX
1
REVIEW
1
PASS
4
INFO
0
Device:
Mobile Desktop
Checks
6
4 PASS 1 REVIEW 1 FIX
D
Green Hosting
Action
Unknown
FIX
Unknown
Info::
Hosting provider could not be identified
Without knowing the provider, we cannot determine their energy sourcing. Check with your hosting provider about their renewable energy commitments.
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 HostingUnable to Determine
Hosting Not identified✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

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
0.31g CO2 per view
PASS
0.31g CO2 per view
Info::
0.31g CO2 per page view
This page transfers 1.1 MB, producing an estimated 0.31g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.06g, network 0.05g, end-user device 0.20g.
Got: 0.31g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 37.3 kg CO2/year
With 10,000 page views per month, this page would generate approximately 37.3 kg of CO2 annually — equivalent to charging 4657 smartphones.

0.31g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 79% of websites

Sustainable Web Design model v4 · Page size: 1.1 MB

Your site
0.31g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.06g
Network
0.05g
End-user device
0.20g
At 10,000 monthly views: Monthly: 3.1 kg · Annual: 37.3 kg · ≈ 4657 smartphone charges
A+
Repeat Visit Weight
97% cached
PASS
97% cached
Info::
97% reduction on repeat visits
Returning visitors download only 37 KB (vs 1122 KB first visit). 31 of 32 resources are served from browser cache, saving 0.30g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.31g)
First visit
1122 KB
Repeat visit
37 KB

97% reduction on repeat visits

Saving 0.30g CO2 per returning visitor

31 resources served from cache · 1 resources re-downloaded

A
Carbon Budget
21th percentile
PASS
21th percentile
Info::
0.31g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 79% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 21th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.31g

21st percentile

Cleaner than 79% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 48% cleaner ✓
vs Target 38% cleaner ✓
A+
Transfer Efficiency
92% efficient
PASS
92% efficient
Info::
Transfer efficiency: 92%
Only 86 KB of potential savings identified. Your page is well-optimized for size.
92% efficient

Total waste: 86 KB (8% of page weight)

Unused JS 86 KB

0.02g unnecessary CO2 per visit

Actual transfer 1122 KB
Theoretical minimum 1036 KB
Potential savings 86 KB (0.02g 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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