https://sitevalue.org
Sustainability
· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
92
GRADE
A
FIX
0
REVIEW
3
PASS
4
INFO
1
Checks
84 PASS 3 REVIEW
BTransfer Efficiency76% efficientREVIEW
Transfer Efficiency
76% efficient
76% efficient
Info::
Transfer efficiency: 76%
An estimated 202 KB (24%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 202 KB of unused JavaScript. This wasted data produces 0.05g of unnecessary CO2 per page view.
Total waste: 202 KB (24% of page weight)
Unused JS 202 KB
0.05g unnecessary CO2 per visit
Actual transfer 856 KB
Theoretical minimum 654 KB
Potential savings 202 KB (0.05g 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+CO2 Per Page Load0.20g CO2 per viewPASS
CO2 Per Page Load
0.20g CO2 per view
0.20g CO2 per view
Info::
0.20g CO2 per page view
This page transfers 0.8 MB, producing an estimated 0.20g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.00g, network 0.04g, end-user device 0.15g.
Got: 0.20g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 23.8 kg CO2/year
With 10,000 page views per month, this page would generate approximately 23.8 kg of CO2 annually — equivalent to charging 2970 smartphones.
Info::
Green hosting reduces data center emissions
0.20g
Carbon Footprint per page view
✓ Below sustainability target (0.50g)
Cleaner than 90% of websites
Sustainable Web Design model v4 · Page size: 0.8 MB
Your site
0.20g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.00g
Network
0.04g
End-user device
0.15g
At 10,000 monthly views: Monthly: 2.0 kg · Annual: 23.8 kg · ≈ 2970 smartphone charges
AGreen HostingGreen (cdn)PASS
Green Hosting
Green (cdn)
Green (cdn)
Info::
Cloudflare CDN uses renewable energy
Since most traffic is served through the CDN, the majority of data transfer energy is renewable.
Info::
Cloudflare: 100% renewable energy for global network since 2019
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 Cloudflare✓
Cloudflare: 100% renewable energy for global network since 2019
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight88% cachedPASS
Repeat Visit Weight
88% cached
88% cached
Info::
88% reduction on repeat visits
Returning visitors download only 103 KB (vs 856 KB first visit). 54 of 56 resources are served from browser cache, saving 0.17g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 0.20g)
First visit
856 KB
Repeat visit
103 KB
88% reduction on repeat visits
Saving 0.17g CO2 per returning visitor
54 resources served from cache · 2 resources re-downloaded
A+Carbon Budget10th percentilePASS
Carbon Budget
10th percentile
10th percentile
Info::
0.20g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 90% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 10th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.20g
10th percentile
Cleaner than 90% of websites
✓ Below the Web Sustainability Guidelines target
vs Median 67% cleaner ✓
vs Target 60% cleaner ✓
Image Optimization12 images, 98 KB total, 0 KB wastedINFO
Image Optimization
12 images, 98 KB total, 0 KB wasted
Image Optimization Audit
Total Images
12
Total Size
98 KB
12 missing dimensions 12 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.