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https://seznam.cz

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
56
GRADE
D
FIX
3
REVIEW
2
PASS
1
INFO
0
Device:
Mobile Desktop
Checks
6
1 PASS 2 REVIEW 3 FIX
F
CO2 Per Page Load
Action
1.69g CO2 per view
FIX
1.69g CO2 per view
Warning::
1.69g CO2 per page view
This page transfers 6.0 MB, producing an estimated 1.69g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.31g, network 0.29g, end-user device 1.08g.
Got: 1.69g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 202.7 kg CO2/year
With 10,000 page views per month, this page would generate approximately 202.7 kg of CO2 annually — equivalent to charging 25334 smartphones.

1.69g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 19% of websites

Sustainable Web Design model v4 · Page size: 6.0 MB

Your site
1.69g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.31g
Network
0.29g
End-user device
1.08g
At 10,000 monthly views: Monthly: 16.9 kg · Annual: 202.7 kg · ≈ 25334 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::
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 Snowplow Analytics✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

F
Carbon Budget
Action
81th percentile
FIX
81th percentile
Warning::
1.69g CO2 — above the median website (0.60g)
Heavier than an estimated 19% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 81th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

1.69g

81st percentile

Cleaner than 19% of websites

✗ Above the median website

vs Median 181% more
vs Target 238% more
B
Transfer Efficiency
83% efficient
REVIEW
83% efficient
Info::
Transfer efficiency: 83%
An estimated 1009 KB (17%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 1009 KB of unused JavaScript. This wasted data produces 0.28g of unnecessary CO2 per page view.
83% efficient

Total waste: 1009 KB (17% of page weight)

Unused JS 1009 KB

0.28g unnecessary CO2 per visit

Actual transfer 6107 KB
Theoretical minimum 5097 KB
Potential savings 1009 KB (0.28g 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
97% cached
PASS
97% cached
Info::
97% reduction on repeat visits
Returning visitors download only 191 KB (vs 6107 KB first visit). 286 of 339 resources are served from browser cache, saving 1.64g CO2 per repeat visit.
Info::
Repeat visit: 0.05g CO2 (first visit: 1.69g)
First visit
6107 KB
Repeat visit
191 KB

97% reduction on repeat visits

Saving 1.64g CO2 per returning visitor

286 resources served from cache · 53 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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