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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
2
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 2 REVIEW 2 FIX
D
CO2 Per Page Load
Action
1.02g CO2 per view
FIX
1.02g CO2 per view
Warning::
1.02g CO2 per page view
This page transfers 4.3 MB, producing an estimated 1.02g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.03g, network 0.21g, end-user device 0.78g.
Got: 1.02g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 122.6 kg CO2/year
With 10,000 page views per month, this page would generate approximately 122.6 kg of CO2 annually — equivalent to charging 15328 smartphones.
Info::
Green hosting reduces data center emissions

1.02g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 38% of websites

Sustainable Web Design model v4 · Page size: 4.3 MB

Your site
1.02g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.03g
Network
0.21g
End-user device
0.78g
At 10,000 monthly views: Monthly: 10.2 kg · Annual: 122.6 kg · ≈ 15328 smartphone charges
D
Carbon Budget
Action
62th percentile
FIX
62th percentile
Warning::
1.02g CO2 — above the median website (0.60g)
Heavier than an estimated 38% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 62th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

1.02g

62nd percentile

Cleaner than 38% of websites

✗ Above the median website

vs Median 70% more
vs Target 104% more
B
Transfer Efficiency
90% efficient
REVIEW
90% efficient
Info::
Transfer efficiency: 90%
An estimated 450 KB (10%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 450 KB of unused JavaScript. This wasted data produces 0.10g of unnecessary CO2 per page view.
90% efficient

Total waste: 450 KB (10% of page weight)

Unused JS 450 KB

0.10g unnecessary CO2 per visit

Actual transfer 4421 KB
Theoretical minimum 3971 KB
Potential savings 450 KB (0.10g 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
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 63 KB (vs 4421 KB first visit). 74 of 76 resources are served from browser cache, saving 1.01g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 1.02g)
First visit
4421 KB
Repeat visit
63 KB

99% reduction on repeat visits

Saving 1.01g CO2 per returning visitor

74 resources served from cache · 2 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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