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https://serenis.it

Sustainability

· 8 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
4
PASS
2
INFO
1
Device:
Mobile Desktop
Checks
8
2 PASS 4 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::
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

B
Carbon Budget
34th percentile
REVIEW
34th percentile
Info::
0.45g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 66% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 34th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.45g

34th percentile

Cleaner than 66% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 25% cleaner ✓
vs Target 10% cleaner ✓
B
Transfer Efficiency
83% efficient
REVIEW
83% efficient
Info::
Transfer efficiency: 83%
An estimated 283 KB (17%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 283 KB of unused JavaScript. This wasted data produces 0.08g of unnecessary CO2 per page view.
83% efficient

Total waste: 283 KB (17% of page weight)

Unused JS 283 KB

0.08g unnecessary CO2 per visit

Actual transfer 1625 KB
Theoretical minimum 1341 KB
Potential savings 283 KB (0.08g CO2)

See Deep Analysis sections above for specific optimizations.

B
Web Font Weight Variants
No detectable Google Fonts weights
REVIEW
No detectable Google Fonts weights
Info::
No detectable Google Fonts weights
The analyzer detects font weights via Google Fonts URL parameters (~70% of font-using sites). Self-hosted fonts and non-Google CDN fonts aren't visible to URL-based detection. If you self-host fonts, manually audit how many @font-face weights you ship -- 2-3 weights per family is typically enough; 5+ is usually unused payload.
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
0.45g CO2 per view
PASS
0.45g CO2 per view
Info::
0.45g CO2 per page view
This page transfers 1.6 MB, producing an estimated 0.45g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.08g, network 0.08g, end-user device 0.29g.
Got: 0.45g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 53.9 kg CO2/year
With 10,000 page views per month, this page would generate approximately 53.9 kg of CO2 annually — equivalent to charging 6742 smartphones.

0.45g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 66% of websites

Sustainable Web Design model v4 · Page size: 1.6 MB

Your site
0.45g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.08g
Network
0.08g
End-user device
0.29g
At 10,000 monthly views: Monthly: 4.5 kg · Annual: 53.9 kg · ≈ 6742 smartphone charges
A+
Repeat Visit Weight
97% cached
PASS
97% cached
Info::
97% reduction on repeat visits
Returning visitors download only 43 KB (vs 1625 KB first visit). 81 of 86 resources are served from browser cache, saving 0.44g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.45g)
First visit
1625 KB
Repeat visit
43 KB

97% reduction on repeat visits

Saving 0.44g CO2 per returning visitor

81 resources served from cache · 5 resources re-downloaded

Image Optimization
156 images, 0 KB total, 0 KB wasted
INFO

Image Optimization Audit

Total Images

156

Total Size

0 KB

Oversized

1

156 missing dimensions 24 missing lazy loading
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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