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https://tuwien.ac.at

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
80
GRADE
B
FIX
1
REVIEW
2
PASS
3
INFO
0
Device:
Mobile Desktop
Checks
6
3 PASS 2 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

B
Transfer Efficiency
82% efficient
REVIEW
82% efficient
Info::
Transfer efficiency: 82%
An estimated 240 KB (18%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 240 KB of unused JavaScript. This wasted data produces 0.07g of unnecessary CO2 per page view.
82% efficient

Total waste: 240 KB (18% of page weight)

Unused JS 240 KB

0.07g unnecessary CO2 per visit

Actual transfer 1364 KB
Theoretical minimum 1123 KB
Potential savings 240 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
0.38g CO2 per view
PASS
0.38g CO2 per view
Info::
0.38g CO2 per page view
This page transfers 1.3 MB, producing an estimated 0.38g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.07g, network 0.07g, end-user device 0.24g.
Got: 0.38g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 45.3 kg CO2/year
With 10,000 page views per month, this page would generate approximately 45.3 kg of CO2 annually — equivalent to charging 5658 smartphones.

0.38g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 73% of websites

Sustainable Web Design model v4 · Page size: 1.3 MB

Your site
0.38g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.07g
Network
0.07g
End-user device
0.24g
At 10,000 monthly views: Monthly: 3.8 kg · Annual: 45.3 kg · ≈ 5658 smartphone charges
A+
Repeat Visit Weight
98% cached
PASS
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 33 KB (vs 1364 KB first visit). 39 of 40 resources are served from browser cache, saving 0.37g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.38g)
First visit
1364 KB
Repeat visit
33 KB

98% reduction on repeat visits

Saving 0.37g CO2 per returning visitor

39 resources served from cache · 1 resources re-downloaded

A
Carbon Budget
27th percentile
PASS
27th percentile
Info::
0.38g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 73% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 27th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.38g

27th percentile

Cleaner than 73% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 37% cleaner ✓
vs Target 25% cleaner ✓
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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