https://nottingham.ac.uk
Sustainability
· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
76
GRADE
C
FIX
2
REVIEW
1
PASS
3
INFO
0
Checks
63 PASS 1 REVIEW 2 FIX
DCO2 Per Page LoadAction1.13g CO2 per viewFIX
CO2 Per Page Load
Action1.13g CO2 per view
1.13g CO2 per view
Warning::
1.13g CO2 per page view
This page transfers 4.8 MB, producing an estimated 1.13g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.03g, network 0.23g, end-user device 0.86g.
Got: 1.13g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 135.0 kg CO2/year
With 10,000 page views per month, this page would generate approximately 135.0 kg of CO2 annually — equivalent to charging 16879 smartphones.
Info::
Green hosting reduces data center emissions
1.13g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 35% of websites
Sustainable Web Design model v4 · Page size: 4.8 MB
Your site
1.13g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.03g
Network
0.23g
End-user device
0.86g
At 10,000 monthly views: Monthly: 11.3 kg · Annual: 135.0 kg · ≈ 16879 smartphone charges
DCarbon BudgetAction65th percentileFIX
Carbon Budget
Action65th percentile
65th percentile
Warning::
1.13g CO2 — above the median website (0.60g)
Heavier than an estimated 35% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 65th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
1.13g
65th percentile
Cleaner than 35% of websites
✗ Above the median website
vs Median 88% more
vs Target 125% more
BGreen HostingGreen (hosting)REVIEW
Green Hosting
Green (hosting)
Green (hosting)
Info::
Zengenti uses renewable energy
Info::
Zengenti: 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 Zengenti✓CDN Not identified✗
Zengenti: Verified by the Green Web Foundation
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight98% cachedPASS
Repeat Visit Weight
98% cached
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 93 KB (vs 4868 KB first visit). 68 of 69 resources are served from browser cache, saving 1.10g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 1.13g)
First visit
4868 KB
Repeat visit
93 KB
98% reduction on repeat visits
Saving 1.10g CO2 per returning visitor
68 resources served from cache · 1 resources re-downloaded
A+Transfer Efficiency99% efficientPASS
Transfer Efficiency
99% efficient
99% efficient
Info::
Transfer efficiency: 99%
Only 62 KB of potential savings identified. Your page is well-optimized for size.
Total waste: 62 KB (1% of page weight)
Unused JS 62 KB
0.01g unnecessary CO2 per visit
Actual transfer 4868 KB
Theoretical minimum 4806 KB
Potential savings 62 KB (0.01g CO2)
See Deep Analysis sections above for specific optimizations.
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: Zengenti
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.