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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
1
REVIEW
3
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 3 REVIEW 1 FIX
D
Carbon Budget
Action
55th percentile
FIX
55th percentile
Warning::
0.78g CO2 — above the median website (0.60g)
Heavier than an estimated 45% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 55th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.78g

55th percentile

Cleaner than 45% of websites

✗ Above the median website

vs Median 30% more
vs Target 55% more
B
CO2 Per Page Load
0.78g CO2 per view
REVIEW
0.78g CO2 per view
Info::
0.78g CO2 per page view
This page transfers 3.3 MB, producing an estimated 0.78g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.16g, end-user device 0.60g.
Got: 0.78g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 93.3 kg CO2/year
With 10,000 page views per month, this page would generate approximately 93.3 kg of CO2 annually — equivalent to charging 11656 smartphones.
Info::
Green hosting reduces data center emissions

0.78g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 45% of websites

Sustainable Web Design model v4 · Page size: 3.3 MB

Your site
0.78g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.02g
Network
0.16g
End-user device
0.60g
At 10,000 monthly views: Monthly: 7.8 kg · Annual: 93.3 kg · ≈ 11656 smartphone charges
C
Transfer Efficiency
Action
63% efficient
REVIEW
63% efficient
Warning::
Transfer efficiency: 63%
An estimated 1227 KB (37%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 1227 KB of unused JavaScript. This wasted data produces 0.28g of unnecessary CO2 per page view.
63% efficient

Total waste: 1227 KB (37% of page weight)

Unused JS 1227 KB

0.28g unnecessary CO2 per visit

Actual transfer 3362 KB
Theoretical minimum 2134 KB
Potential savings 1227 KB (0.28g 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 74 KB (vs 3362 KB first visit). 109 of 116 resources are served from browser cache, saving 0.76g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 0.78g)
First visit
3362 KB
Repeat visit
74 KB

98% reduction on repeat visits

Saving 0.76g CO2 per returning visitor

109 resources served from cache · 7 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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