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Sustainability

· 7 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
67
GRADE
D
FIX
2
REVIEW
2
PASS
3
INFO
0
Device:
Mobile Desktop
Checks
7
3 PASS 2 REVIEW 2 FIX
F
CO2 Per Page Load
Action
3.89g CO2 per view
FIX
3.89g CO2 per view
Critical::
3.89g CO2 per page view
This page transfers 16.4 MB, producing an estimated 3.89g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.10g, network 0.80g, end-user device 2.98g.
Got: 3.89g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 466.2 kg CO2/year
With 10,000 page views per month, this page would generate approximately 466.2 kg of CO2 annually — equivalent to charging 58275 smartphones.
Info::
Green hosting reduces data center emissions

3.89g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 5% of websites

Sustainable Web Design model v4 · Page size: 16.4 MB

Your site
3.89g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.10g
Network
0.80g
End-user device
2.98g
At 10,000 monthly views: Monthly: 38.9 kg · Annual: 466.2 kg · ≈ 58275 smartphone charges
F
Carbon Budget
Action
95th percentile
FIX
95th percentile
Warning::
3.89g CO2 — above the median website (0.60g)
Heavier than an estimated 5% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 95th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

3.89g

95th percentile

Cleaner than 5% of websites

✗ Above the median website

vs Median 548% more
vs Target 677% more
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
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 Not identified✗CDN Fastly✓

Fastly: 100% renewable energy for edge network

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
97% cached
PASS
97% cached
Info::
97% reduction on repeat visits
Returning visitors download only 516 KB (vs 16807 KB first visit). 137 of 140 resources are served from browser cache, saving 3.77g CO2 per repeat visit.
Info::
Repeat visit: 0.12g CO2 (first visit: 3.89g)
First visit
16807 KB
Repeat visit
516 KB

97% reduction on repeat visits

Saving 3.77g CO2 per returning visitor

137 resources served from cache · 3 resources re-downloaded

A+
Transfer Efficiency
90% efficient
PASS
90% efficient
Info::
Transfer efficiency: 90%
Only 1611 KB of potential savings identified. Your page is well-optimized for size.
90% efficient

Total waste: 1611 KB (10% of page weight)

Unused JS 1611 KB

0.37g unnecessary CO2 per visit

Actual transfer 16807 KB
Theoretical minimum 15196 KB
Potential savings 1611 KB (0.37g CO2)

See Deep Analysis sections above for specific optimizations.

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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