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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::
0.79g 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

0.79g

55th percentile

Cleaner than 45% of websites

✗ Above the median website

vs Median 31% more
vs Target 57% more
B
CO2 Per Page Load
0.79g CO2 per view
REVIEW
0.79g CO2 per view
Info::
0.79g CO2 per page view
This page transfers 3.3 MB, producing an estimated 0.79g 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: 0.79g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 94.3 kg CO2/year
With 10,000 page views per month, this page would generate approximately 94.3 kg of CO2 annually — equivalent to charging 11783 smartphones.
Info::
Green hosting reduces data center emissions

0.79g

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
0.79g
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: 7.9 kg · Annual: 94.3 kg · ≈ 11783 smartphone charges
C
Transfer Efficiency
Action
62% efficient
REVIEW
62% efficient
Warning::
Transfer efficiency: 62%
An estimated 1301 KB (38%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 1301 KB of unused JavaScript. This wasted data produces 0.30g of unnecessary CO2 per page view.
62% efficient

Total waste: 1301 KB (38% of page weight)

Unused JS 1301 KB

0.30g unnecessary CO2 per visit

Actual transfer 3398 KB
Theoretical minimum 2097 KB
Potential savings 1301 KB (0.30g 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 3398 KB first visit). 104 of 111 resources are served from browser cache, saving 0.77g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 0.79g)
First visit
3398 KB
Repeat visit
74 KB

98% reduction on repeat visits

Saving 0.77g CO2 per returning visitor

104 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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