https://uu.nl
Sustainability
· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
86
GRADE
B
FIX
0
REVIEW
2
PASS
4
INFO
0
Checks
64 PASS 2 REVIEW
BGreen HostingGreen (hosting)REVIEW
Green Hosting
Green (hosting)
Green (hosting)
Info::
Combell uses renewable energy
Info::
Combell: Verified by the Green Web Foundation
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 Hosting✓ Green Hosted
Hosting Combell✓CDN Not identified✗
Combell: Verified by the Green Web Foundation
Based on known provider commitments. Verify at thegreenwebfoundation.org
BTransfer Efficiency85% efficientREVIEW
Transfer Efficiency
85% efficient
85% efficient
Info::
Transfer efficiency: 85%
An estimated 226 KB (15%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 226 KB of unused JavaScript. This wasted data produces 0.05g of unnecessary CO2 per page view.
Total waste: 226 KB (15% of page weight)
Unused JS 226 KB
0.05g unnecessary CO2 per visit
Actual transfer 1553 KB
Theoretical minimum 1326 KB
Potential savings 226 KB (0.05g CO2)
See Deep Analysis sections above for specific optimizations.
ACO2 Per Page Load0.36g CO2 per viewPASS
CO2 Per Page Load
0.36g CO2 per view
0.36g CO2 per view
Info::
0.36g CO2 per page view
This page transfers 1.5 MB, producing an estimated 0.36g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.07g, end-user device 0.28g.
Got: 0.36g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 43.1 kg CO2/year
With 10,000 page views per month, this page would generate approximately 43.1 kg of CO2 annually — equivalent to charging 5384 smartphones.
Info::
Green hosting reduces data center emissions
0.36g
Carbon Footprint per page view
✓ Below sustainability target (0.50g)
Cleaner than 75% of websites
Sustainable Web Design model v4 · Page size: 1.5 MB
Your site
0.36g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.01g
Network
0.07g
End-user device
0.28g
At 10,000 monthly views: Monthly: 3.6 kg · Annual: 43.1 kg · ≈ 5384 smartphone charges
A+Repeat Visit Weight99% cachedPASS
Repeat Visit Weight
99% cached
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 8 KB (vs 1553 KB first visit). 34 of 35 resources are served from browser cache, saving 0.36g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 0.36g)
First visit
1553 KB
Repeat visit
8 KB
99% reduction on repeat visits
Saving 0.36g CO2 per returning visitor
34 resources served from cache · 1 resources re-downloaded
ACarbon Budget25th percentilePASS
Carbon Budget
25th percentile
25th percentile
Info::
0.36g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 75% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 25th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.36g
25th percentile
Cleaner than 75% of websites
✓ Below the Web Sustainability Guidelines target
vs Median 40% cleaner ✓
vs Target 28% cleaner ✓
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
Whether the site is served from green-energy infrastructure
Green Hosting
This site is hosted on green energy infrastructure
Provider: Combell
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.