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Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
73
GRADE
C
FIX
2
REVIEW
2
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 2 REVIEW 2 FIX
D
CO2 Per Page Load
Action
0.95g CO2 per view
FIX
0.95g CO2 per view
Info::
0.95g CO2 per page view
This page transfers 4.0 MB, producing an estimated 0.95g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.20g, end-user device 0.73g.
Got: 0.95g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 114.1 kg CO2/year
With 10,000 page views per month, this page would generate approximately 114.1 kg of CO2 annually — equivalent to charging 14263 smartphones.
Info::
Green hosting reduces data center emissions

0.95g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 40% of websites

Sustainable Web Design model v4 · Page size: 4.0 MB

Your site
0.95g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.02g
Network
0.20g
End-user device
0.73g
At 10,000 monthly views: Monthly: 9.5 kg · Annual: 114.1 kg · ≈ 14263 smartphone charges
D
Carbon Budget
Action
60th percentile
FIX
60th percentile
Warning::
0.95g CO2 — above the median website (0.60g)
Heavier than an estimated 40% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 60th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.95g

60th percentile

Cleaner than 40% of websites

✗ Above the median website

vs Median 58% more
vs Target 90% more
B
Transfer Efficiency
84% efficient
REVIEW
84% efficient
Info::
Transfer efficiency: 84%
An estimated 642 KB (16%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 642 KB of unused JavaScript. This wasted data produces 0.15g of unnecessary CO2 per page view.
84% efficient

Total waste: 642 KB (16% of page weight)

Unused JS 642 KB

0.15g unnecessary CO2 per visit

Actual transfer 4113 KB
Theoretical minimum 3471 KB
Potential savings 642 KB (0.15g 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
Green Hosting
Green (cdn)
PASS
Green (cdn)
Info::
Fastly CDN uses renewable energy
Since most traffic is served through the CDN, the majority of data transfer energy is renewable.
Info::
Fastly: 100% renewable energy for edge network
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 Not identified✗CDN Fastly✓

Fastly: 100% renewable energy for edge network

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
96% cached
PASS
96% cached
Info::
96% reduction on repeat visits
Returning visitors download only 165 KB (vs 4113 KB first visit). 172 of 176 resources are served from browser cache, saving 0.91g CO2 per repeat visit.
Info::
Repeat visit: 0.04g CO2 (first visit: 0.95g)
First visit
4113 KB
Repeat visit
165 KB

96% reduction on repeat visits

Saving 0.91g CO2 per returning visitor

172 resources served from cache · 4 resources re-downloaded

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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