Skip to content
https://edweek.org

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
60
GRADE
D
FIX
3
REVIEW
2
PASS
1
INFO
0
Device:
Mobile Desktop
Checks
6
1 PASS 2 REVIEW 3 FIX
D
CO2 Per Page Load
Action
1.15g CO2 per view
FIX
1.15g CO2 per view
Warning::
1.15g CO2 per page view
This page transfers 4.1 MB, producing an estimated 1.15g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.21g, network 0.20g, end-user device 0.74g.
Got: 1.15g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 138.5 kg CO2/year
With 10,000 page views per month, this page would generate approximately 138.5 kg of CO2 annually — equivalent to charging 17318 smartphones.

1.15g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 35% of websites

Sustainable Web Design model v4 · Page size: 4.1 MB

Your site
1.15g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.21g
Network
0.20g
End-user device
0.74g
At 10,000 monthly views: Monthly: 11.5 kg · Annual: 138.5 kg · ≈ 17318 smartphone charges
D
Green Hosting
Action
Not green
FIX
Not green
Info::
No confirmed renewable energy commitment detected
Consider providers like Cloudflare, Google Cloud, or Vercel that match 100% of their energy use with renewables.
Info::
AWS: Renewable energy varies by region; committed to 100% by 2025
Info::
AWS CloudFront: Renewable varies by edge location
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 HostingNot Green Hosted
Hosting AWS✗CDN AWS CloudFront✗

AWS: Renewable energy varies by region; committed to 100% by 2025

AWS CloudFront: Renewable varies by edge location

Based on known provider commitments. Verify at thegreenwebfoundation.org

D
Carbon Budget
Action
65th percentile
FIX
65th percentile
Warning::
1.15g CO2 — above the median website (0.60g)
Heavier than an estimated 35% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 65th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

1.15g

65th percentile

Cleaner than 35% of websites

✗ Above the median website

vs Median 92% more
vs Target 131% more
C
Transfer Efficiency
Action
67% efficient
REVIEW
67% efficient
Warning::
Transfer efficiency: 67%
An estimated 1365 KB (33%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 1365 KB of unused JavaScript. This wasted data produces 0.38g of unnecessary CO2 per page view.
67% efficient

Total waste: 1365 KB (33% of page weight)

Unused JS 1365 KB

0.38g unnecessary CO2 per visit

Actual transfer 4174 KB
Theoretical minimum 2809 KB
Potential savings 1365 KB (0.38g 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+
Repeat Visit Weight
98% cached
PASS
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 100 KB (vs 4174 KB first visit). 126 of 137 resources are served from browser cache, saving 1.13g CO2 per repeat visit.
Info::
Repeat visit: 0.03g CO2 (first visit: 1.15g)
First visit
4174 KB
Repeat visit
100 KB

98% reduction on repeat visits

Saving 1.13g CO2 per returning visitor

126 resources served from cache · 11 resources re-downloaded

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback