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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
0.57g CO2 per view
REVIEW
0.57g CO2 per view
Info::
0.57g CO2 per page view
This page transfers 2.4 MB, producing an estimated 0.57g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.12g, end-user device 0.44g.
Got: 0.57g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 68.6 kg CO2/year
With 10,000 page views per month, this page would generate approximately 68.6 kg of CO2 annually — equivalent to charging 8570 smartphones.
Info::
Green hosting reduces data center emissions

0.57g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 53% of websites

Sustainable Web Design model v4 · Page size: 2.4 MB

Your site
0.57g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.01g
Network
0.12g
End-user device
0.44g
At 10,000 monthly views: Monthly: 5.7 kg · Annual: 68.6 kg · ≈ 8570 smartphone charges
B
Carbon Budget
47th percentile
REVIEW
47th percentile
Info::
0.57g CO2 — below the median website (0.60g)
Better than an estimated 53% of websites, but above the sustainability target of 0.50g. Reducing page weight would help reach the target.
Info::
Estimated 47th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.57g

47th percentile

Cleaner than 53% of websites

✗ Above the median website

vs Median 5% cleaner ✓
vs Target 14% more
B
Transfer Efficiency
85% efficient
REVIEW
85% efficient
Info::
Transfer efficiency: 85%
An estimated 358 KB (15%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 358 KB of unused JavaScript. This wasted data produces 0.08g of unnecessary CO2 per page view.
85% efficient

Total waste: 358 KB (15% of page weight)

Unused JS 358 KB

0.08g unnecessary CO2 per visit

Actual transfer 2471 KB
Theoretical minimum 2113 KB
Potential savings 358 KB (0.08g 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 53 KB (vs 2471 KB first visit). 104 of 105 resources are served from browser cache, saving 0.56g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.57g)
First visit
2471 KB
Repeat visit
53 KB

98% reduction on repeat visits

Saving 0.56g CO2 per returning visitor

104 resources served from cache · 1 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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