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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
1
REVIEW
3
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 3 REVIEW 1 FIX
D
Carbon Budget
Action
52th percentile
FIX
52th percentile
Warning::
0.70g CO2 — above the median website (0.60g)
Heavier than an estimated 48% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 52th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.70g

52nd percentile

Cleaner than 48% of websites

✗ Above the median website

vs Median 17% more
vs Target 40% more
B
CO2 Per Page Load
0.70g CO2 per view
REVIEW
0.70g CO2 per view
Info::
0.70g CO2 per page view
This page transfers 3.0 MB, producing an estimated 0.70g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.14g, end-user device 0.54g.
Got: 0.70g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 84.1 kg CO2/year
With 10,000 page views per month, this page would generate approximately 84.1 kg of CO2 annually — equivalent to charging 10512 smartphones.
Info::
Green hosting reduces data center emissions

0.70g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 48% of websites

Sustainable Web Design model v4 · Page size: 3.0 MB

Your site
0.70g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.02g
Network
0.14g
End-user device
0.54g
At 10,000 monthly views: Monthly: 7.0 kg · Annual: 84.1 kg · ≈ 10512 smartphone charges
B
Transfer Efficiency
85% efficient
REVIEW
85% efficient
Info::
Transfer efficiency: 85%
An estimated 452 KB (15%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 452 KB of unused JavaScript. This wasted data produces 0.10g of unnecessary CO2 per page view.
85% efficient

Total waste: 452 KB (15% of page weight)

Unused JS 452 KB

0.10g unnecessary CO2 per visit

Actual transfer 3031 KB
Theoretical minimum 2579 KB
Potential savings 452 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 40 KB (vs 3031 KB first visit). 148 of 151 resources are served from browser cache, saving 0.69g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.70g)
First visit
3031 KB
Repeat visit
40 KB

99% reduction on repeat visits

Saving 0.69g CO2 per returning visitor

148 resources served from cache · 3 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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