https://kew.org
Sustainability
· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
82
GRADE
B
FIX
1
REVIEW
3
PASS
2
INFO
0
Checks
62 PASS 3 REVIEW 1 FIX
DGreen HostingActionNot greenFIX
Green Hosting
ActionNot green
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
BCO2 Per Page Load0.59g CO2 per viewREVIEW
CO2 Per Page Load
0.59g CO2 per view
0.59g CO2 per view
Info::
0.59g CO2 per page view
This page transfers 2.1 MB, producing an estimated 0.59g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.11g, network 0.10g, end-user device 0.38g.
Got: 0.59g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 70.9 kg CO2/year
With 10,000 page views per month, this page would generate approximately 70.9 kg of CO2 annually — equivalent to charging 8864 smartphones.
0.59g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 51% of websites
Sustainable Web Design model v4 · Page size: 2.1 MB
Your site
0.59g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.11g
Network
0.10g
End-user device
0.38g
At 10,000 monthly views: Monthly: 5.9 kg · Annual: 70.9 kg · ≈ 8864 smartphone charges
BCarbon Budget49th percentileREVIEW
Carbon Budget
49th percentile
49th percentile
Info::
0.59g CO2 — below the median website (0.60g)
Better than an estimated 51% of websites, but above the sustainability target of 0.50g. Reducing page weight would help reach the target.
Info::
Estimated 49th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.59g
49th percentile
Cleaner than 51% of websites
✗ Above the median website
vs Median 2% cleaner ✓
vs Target 18% more
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
ActionWhether the site is served from green-energy infrastructure
Green Hosting
No green hosting detected
A+Repeat Visit Weight99% cachedPASS
Repeat Visit Weight
99% cached
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 25 KB (vs 2136 KB first visit). 56 of 57 resources are served from browser cache, saving 0.58g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.59g)
First visit
2136 KB
Repeat visit
25 KB
99% reduction on repeat visits
Saving 0.58g CO2 per returning visitor
56 resources served from cache · 1 resources re-downloaded
A+Transfer Efficiency95% efficientPASS
Transfer Efficiency
95% efficient
95% efficient
Info::
Transfer efficiency: 95%
Only 102 KB of potential savings identified. Your page is well-optimized for size.
Total waste: 102 KB (5% of page weight)
Unused JS 102 KB
0.03g unnecessary CO2 per visit
Actual transfer 2136 KB
Theoretical minimum 2034 KB
Potential savings 102 KB (0.03g 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.