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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
77
GRADE
C
FIX
0
REVIEW
4
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 4 REVIEW
B
CO2 Per Page Load
0.53g CO2 per view
REVIEW
0.53g CO2 per view
Info::
0.53g CO2 per page view
This page transfers 2.2 MB, producing an estimated 0.53g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.11g, end-user device 0.41g.
Got: 0.53g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 63.8 kg CO2/year
With 10,000 page views per month, this page would generate approximately 63.8 kg of CO2 annually — equivalent to charging 7971 smartphones.
Info::
Green hosting reduces data center emissions

0.53g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 57% of websites

Sustainable Web Design model v4 · Page size: 2.2 MB

Your site
0.53g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.01g
Network
0.11g
End-user device
0.41g
At 10,000 monthly views: Monthly: 5.3 kg · Annual: 63.8 kg · ≈ 7971 smartphone charges
B
Carbon Budget
43th percentile
REVIEW
43th percentile
Info::
0.53g CO2 — below the median website (0.60g)
Better than an estimated 57% of websites, but above the sustainability target of 0.50g. Reducing page weight would help reach the target.
Info::
Estimated 43th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.53g

43rd percentile

Cleaner than 57% of websites

✗ Above the median website

vs Median 11% cleaner ✓
vs Target 6% more
C
Transfer Efficiency
Action
75% efficient
REVIEW
75% efficient
Warning::
Transfer efficiency: 75%
An estimated 576 KB (25%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 576 KB of unused JavaScript. This wasted data produces 0.13g of unnecessary CO2 per page view.
75% efficient

Total waste: 576 KB (25% of page weight)

Unused JS 576 KB

0.13g unnecessary CO2 per visit

Actual transfer 2299 KB
Theoretical minimum 1722 KB
Potential savings 576 KB (0.13g 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 48 KB (vs 2299 KB first visit). 156 of 163 resources are served from browser cache, saving 0.52g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.53g)
First visit
2299 KB
Repeat visit
48 KB

98% reduction on repeat visits

Saving 0.52g CO2 per returning visitor

156 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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