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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
81
GRADE
B
FIX
0
REVIEW
4
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 4 REVIEW
B
CO2 Per Page Load
0.54g CO2 per view
REVIEW
0.54g CO2 per view
Info::
0.54g CO2 per page view
This page transfers 2.3 MB, producing an estimated 0.54g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.11g, end-user device 0.42g.
Got: 0.54g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 65.1 kg CO2/year
With 10,000 page views per month, this page would generate approximately 65.1 kg of CO2 annually — equivalent to charging 8141 smartphones.
Info::
Green hosting reduces data center emissions

0.54g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 56% of websites

Sustainable Web Design model v4 · Page size: 2.3 MB

Your site
0.54g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.01g
Network
0.11g
End-user device
0.42g
At 10,000 monthly views: Monthly: 5.4 kg · Annual: 65.1 kg · ≈ 8141 smartphone charges
B
Carbon Budget
44th percentile
REVIEW
44th percentile
Info::
0.54g CO2 — below the median website (0.60g)
Better than an estimated 56% of websites, but above the sustainability target of 0.50g. Reducing page weight would help reach the target.
Info::
Estimated 44th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.54g

44th percentile

Cleaner than 56% of websites

✗ Above the median website

vs Median 10% cleaner ✓
vs Target 9% more
B
Transfer Efficiency
75% efficient
REVIEW
75% efficient
Info::
Transfer efficiency: 75%
An estimated 584 KB (25%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 584 KB of unused JavaScript. This wasted data produces 0.14g of unnecessary CO2 per page view.
75% efficient

Total waste: 584 KB (25% of page weight)

Unused JS 584 KB

0.14g unnecessary CO2 per visit

Actual transfer 2348 KB
Theoretical minimum 1763 KB
Potential savings 584 KB (0.14g 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 Pantheon✗CDN Fastly✓

Fastly: 100% renewable energy for edge network

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
98% cached
PASS
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 47 KB (vs 2348 KB first visit). 157 of 163 resources are served from browser cache, saving 0.53g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.54g)
First visit
2348 KB
Repeat visit
47 KB

98% reduction on repeat visits

Saving 0.53g CO2 per returning visitor

157 resources served from cache · 6 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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