https://www.jcl.energy
Sustainability
· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
75
GRADE
C
FIX
3
REVIEW
2
PASS
2
INFO
1
Checks
82 PASS 2 REVIEW 3 FIX
DCO2 Per Page LoadAction1.09g CO2 per viewFIX
CO2 Per Page Load
Action1.09g CO2 per view
1.09g CO2 per view
Warning::
1.09g CO2 per page view
This page transfers 3.8 MB, producing an estimated 1.09g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.20g, network 0.19g, end-user device 0.70g.
Got: 1.09g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 130.3 kg CO2/year
With 10,000 page views per month, this page would generate approximately 130.3 kg of CO2 annually — equivalent to charging 16289 smartphones.
1.09g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 37% of websites
Sustainable Web Design model v4 · Page size: 3.8 MB
Your site
1.09g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.20g
Network
0.19g
End-user device
0.70g
At 10,000 monthly views: Monthly: 10.9 kg · Annual: 130.3 kg · ≈ 16289 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::
AWS: Renewable energy varies by region; committed to 100% by 2025
Info::
AWS CloudFront: Renewable varies by edge location
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 AWS✗CDN AWS CloudFront✗
AWS: Renewable energy varies by region; committed to 100% by 2025
AWS CloudFront: Renewable varies by edge location
Based on known provider commitments. Verify at thegreenwebfoundation.org
DCarbon BudgetAction63th percentileFIX
Carbon Budget
Action63th percentile
63th percentile
Warning::
1.09g CO2 — above the median website (0.60g)
Heavier than an estimated 37% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 63th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
1.09g
63rd percentile
Cleaner than 37% of websites
✗ Above the median website
vs Median 81% more
vs Target 117% more
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 Weight99% cachedPASS
Repeat Visit Weight
99% cached
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 22 KB (vs 3926 KB first visit). 74 of 75 resources are served from browser cache, saving 1.08g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 1.09g)
First visit
3926 KB
Repeat visit
22 KB
99% reduction on repeat visits
Saving 1.08g CO2 per returning visitor
74 resources served from cache · 1 resources re-downloaded
A+Transfer Efficiency91% efficientPASS
Transfer Efficiency
91% efficient
91% efficient
Info::
Transfer efficiency: 91%
Only 346 KB of potential savings identified. Your page is well-optimized for size.
Total waste: 346 KB (9% of page weight)
Unused JS 346 KB
0.10g unnecessary CO2 per visit
Actual transfer 3926 KB
Theoretical minimum 3579 KB
Potential savings 346 KB (0.10g CO2)
See Deep Analysis sections above for specific optimizations.
Image Optimization15 images, 501 KB total, 363 KB wastedINFO
Image Optimization
15 images, 501 KB total, 363 KB wasted
Image Optimization Audit
Total Images
15
Total Size
501 KB
Oversized
3
Wasted
363 KB
4 missing dimensions 7 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.