https://www.zaanstad.nl
Sustainability
· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
78
GRADE
C
FIX
1
REVIEW
4
PASS
2
INFO
1
Checks
82 PASS 4 REVIEW 1 FIX
DCarbon BudgetAction54th percentileFIX
Carbon Budget
Action54th percentile
54th percentile
Warning::
0.75g CO2 — above the median website (0.60g)
Heavier than an estimated 46% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 54th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.75g
54th percentile
Cleaner than 46% of websites
✗ Above the median website
vs Median 25% more
vs Target 51% more
BCO2 Per Page Load0.75g CO2 per viewREVIEW
CO2 Per Page Load
0.75g CO2 per view
0.75g CO2 per view
Info::
0.75g CO2 per page view
This page transfers 3.2 MB, producing an estimated 0.75g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.02g, network 0.16g, end-user device 0.58g.
Got: 0.75g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 90.3 kg CO2/year
With 10,000 page views per month, this page would generate approximately 90.3 kg of CO2 annually — equivalent to charging 11289 smartphones.
Info::
Green hosting reduces data center emissions
0.75g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 46% of websites
Sustainable Web Design model v4 · Page size: 3.2 MB
Your site
0.75g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.02g
Network
0.16g
End-user device
0.58g
At 10,000 monthly views: Monthly: 7.5 kg · Annual: 90.3 kg · ≈ 11289 smartphone charges
BGreen HostingGreen (hosting)REVIEW
Green Hosting
Green (hosting)
Green (hosting)
Info::
Previder BV uses renewable energy
Info::
Previder BV: Verified by the Green Web Foundation
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 Previder BV✓CDN Not identified✗
Previder BV: Verified by the Green Web Foundation
Based on known provider commitments. Verify at thegreenwebfoundation.org
BTransfer Efficiency81% efficientREVIEW
Transfer Efficiency
81% efficient
81% efficient
Info::
Transfer efficiency: 81%
An estimated 624 KB (19%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 624 KB of unused JavaScript. This wasted data produces 0.14g of unnecessary CO2 per page view.
Total waste: 624 KB (19% of page weight)
Unused JS 624 KB
0.14g unnecessary CO2 per visit
Actual transfer 3256 KB
Theoretical minimum 2632 KB
Potential savings 624 KB (0.14g 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.
A+Repeat Visit Weight99% cachedPASS
Repeat Visit Weight
99% cached
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 25 KB (vs 3256 KB first visit). 52 of 53 resources are served from browser cache, saving 0.75g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.75g)
First visit
3256 KB
Repeat visit
25 KB
99% reduction on repeat visits
Saving 0.75g CO2 per returning visitor
52 resources served from cache · 1 resources re-downloaded
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
Whether the site is served from green-energy infrastructure
Green Hosting
This site is hosted on green energy infrastructure
Provider: Previder BV
Image Optimization9 images, 356 KB total, 293 KB wastedINFO
Image Optimization
9 images, 356 KB total, 293 KB wasted
Image Optimization Audit
Total Images
9
Total Size
356 KB
Oversized
2
Wasted
293 KB
7 missing dimensions 5 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.