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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
1
PASS
3
INFO
0
Device:
Mobile Desktop
Checks
6
3 PASS 1 REVIEW 2 FIX
D
CO2 Per Page Load
Action
1.19g CO2 per view
FIX
1.19g CO2 per view
Warning::
1.19g CO2 per page view
This page transfers 5.0 MB, producing an estimated 1.19g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.03g, network 0.25g, end-user device 0.91g.
Got: 1.19g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 142.2 kg CO2/year
With 10,000 page views per month, this page would generate approximately 142.2 kg of CO2 annually — equivalent to charging 17778 smartphones.
Info::
Green hosting reduces data center emissions

1.19g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 34% of websites

Sustainable Web Design model v4 · Page size: 5.0 MB

Your site
1.19g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.03g
Network
0.25g
End-user device
0.91g
At 10,000 monthly views: Monthly: 11.9 kg · Annual: 142.2 kg · ≈ 17778 smartphone charges
D
Carbon Budget
Action
66th percentile
FIX
66th percentile
Warning::
1.19g CO2 — above the median website (0.60g)
Heavier than an estimated 34% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 66th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

1.19g

66th percentile

Cleaner than 34% of websites

✗ Above the median website

vs Median 98% more
vs Target 137% more
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
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 63 KB (vs 5127 KB first visit). 80 of 82 resources are served from browser cache, saving 1.17g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 1.19g)
First visit
5127 KB
Repeat visit
63 KB

99% reduction on repeat visits

Saving 1.17g CO2 per returning visitor

80 resources served from cache · 2 resources re-downloaded

A+
Transfer Efficiency
91% efficient
PASS
91% efficient
Info::
Transfer efficiency: 91%
Only 449 KB of potential savings identified. Your page is well-optimized for size.
91% efficient

Total waste: 449 KB (9% of page weight)

Unused JS 449 KB

0.10g unnecessary CO2 per visit

Actual transfer 5127 KB
Theoretical minimum 4678 KB
Potential savings 449 KB (0.10g 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.

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