https://bnnvara.nl
Sustainability
· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
68
GRADE
D
FIX
3
REVIEW
3
PASS
1
INFO
1
Checks
81 PASS 3 REVIEW 3 FIX
DCO2 Per Page LoadAction0.86g CO2 per viewFIX
CO2 Per Page Load
Action0.86g CO2 per view
0.86g CO2 per view
Info::
0.86g CO2 per page view
This page transfers 3.0 MB, producing an estimated 0.86g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.16g, network 0.15g, end-user device 0.55g.
Got: 0.86g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 103.6 kg CO2/year
With 10,000 page views per month, this page would generate approximately 103.6 kg of CO2 annually — equivalent to charging 12945 smartphones.
0.86g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 43% of websites
Sustainable Web Design model v4 · Page size: 3.0 MB
Your site
0.86g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.16g
Network
0.15g
End-user device
0.55g
At 10,000 monthly views: Monthly: 8.6 kg · Annual: 103.6 kg · ≈ 12945 smartphone charges
DGreen HostingActionNot greenFIX
Green Hosting
ActionNot green
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 Next.js✗CDN Not identified✗
Based on known provider commitments. Verify at thegreenwebfoundation.org
DCarbon BudgetAction57th percentileFIX
Carbon Budget
Action57th percentile
57th percentile
Warning::
0.86g CO2 — above the median website (0.60g)
Heavier than an estimated 43% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 57th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.86g
57th percentile
Cleaner than 43% of websites
✗ Above the median website
vs Median 44% more
vs Target 73% more
BTransfer Efficiency81% efficientREVIEW
Transfer Efficiency
81% efficient
81% efficient
Info::
Transfer efficiency: 81%
An estimated 603 KB (19%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 603 KB of unused JavaScript. This wasted data produces 0.17g of unnecessary CO2 per page view.
Total waste: 603 KB (19% of page weight)
Unused JS 603 KB
0.17g unnecessary CO2 per visit
Actual transfer 3120 KB
Theoretical minimum 2516 KB
Potential savings 603 KB (0.17g CO2)
See Deep Analysis sections above for specific optimizations.
BWeb Font Weight VariantsNo detectable Google Fonts weightsREVIEW
Web Font Weight Variants
No detectable Google Fonts weights
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.
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
ActionWhether the site is served from green-energy infrastructure
Green Hosting
No green hosting detected
A+Repeat Visit Weight98% cachedPASS
Repeat Visit Weight
98% cached
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 57 KB (vs 3120 KB first visit). 161 of 165 resources are served from browser cache, saving 0.85g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 0.86g)
First visit
3120 KB
Repeat visit
57 KB
98% reduction on repeat visits
Saving 0.85g CO2 per returning visitor
161 resources served from cache · 4 resources re-downloaded
Image Optimization57 images, 6 KB total, 0 KB wastedINFO
Image Optimization
57 images, 6 KB total, 0 KB wasted
Image Optimization Audit
Total Images
57
Total Size
6 KB
57 missing dimensions 50 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.