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https://sleepfoundation.org

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
75
GRADE
C
FIX
1
REVIEW
3
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 3 REVIEW 1 FIX
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::
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 Amazon Web Services✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

B
Carbon Budget
33th percentile
REVIEW
33th percentile
Info::
0.44g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 67% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 33th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.44g

33rd percentile

Cleaner than 67% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 27% cleaner ✓
vs Target 12% cleaner ✓
B
Transfer Efficiency
81% efficient
REVIEW
81% efficient
Info::
Transfer efficiency: 81%
An estimated 306 KB (19%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 306 KB of unused JavaScript. This wasted data produces 0.08g of unnecessary CO2 per page view.
81% efficient

Total waste: 306 KB (19% of page weight)

Unused JS 306 KB

0.08g unnecessary CO2 per visit

Actual transfer 1584 KB
Theoretical minimum 1278 KB
Potential savings 306 KB (0.08g 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
CO2 Per Page Load
0.44g CO2 per view
PASS
0.44g CO2 per view
Info::
0.44g CO2 per page view
This page transfers 1.5 MB, producing an estimated 0.44g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.08g, network 0.08g, end-user device 0.28g.
Got: 0.44g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 52.6 kg CO2/year
With 10,000 page views per month, this page would generate approximately 52.6 kg of CO2 annually — equivalent to charging 6574 smartphones.

0.44g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 67% of websites

Sustainable Web Design model v4 · Page size: 1.5 MB

Your site
0.44g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.08g
Network
0.08g
End-user device
0.28g
At 10,000 monthly views: Monthly: 4.4 kg · Annual: 52.6 kg · ≈ 6574 smartphone charges
A+
Repeat Visit Weight
98% cached
PASS
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 38 KB (vs 1584 KB first visit). 87 of 88 resources are served from browser cache, saving 0.43g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.44g)
First visit
1584 KB
Repeat visit
38 KB

98% reduction on repeat visits

Saving 0.43g CO2 per returning visitor

87 resources served from cache · 1 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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