https://heart.org
Sustainability
· 6 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
0
PASS
3
INFO
0
Checks
63 PASS 3 FIX
DCO2 Per Page LoadAction1.12g CO2 per viewFIX
CO2 Per Page Load
Action1.12g CO2 per view
1.12g CO2 per view
Warning::
1.12g CO2 per page view
This page transfers 4.7 MB, producing an estimated 1.12g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.03g, network 0.23g, end-user device 0.86g.
Got: 1.12g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 134.3 kg CO2/year
With 10,000 page views per month, this page would generate approximately 134.3 kg of CO2 annually — equivalent to charging 16788 smartphones.
Info::
Green hosting reduces data center emissions
1.12g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 36% of websites
Sustainable Web Design model v4 · Page size: 4.7 MB
Your site
1.12g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.03g
Network
0.23g
End-user device
0.86g
At 10,000 monthly views: Monthly: 11.2 kg · Annual: 134.3 kg · ≈ 16788 smartphone charges
DCarbon BudgetAction64th percentileFIX
Carbon Budget
Action64th percentile
64th percentile
Warning::
1.12g CO2 — above the median website (0.60g)
Heavier than an estimated 36% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 64th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
1.12g
64th percentile
Cleaner than 36% of websites
✗ Above the median website
vs Median 87% more
vs Target 124% more
DTransfer EfficiencyAction55% efficientFIX
Transfer Efficiency
Action55% efficient
55% efficient
Warning::
Transfer efficiency: 55%
An estimated 2158 KB (45%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 2158 KB of unused JavaScript. This wasted data produces 0.50g of unnecessary CO2 per page view.
Total waste: 2158 KB (45% of page weight)
Unused JS 2158 KB
0.50g unnecessary CO2 per visit
Actual transfer 4842 KB
Theoretical minimum 2683 KB
Potential savings 2158 KB (0.50g CO2)
See Deep Analysis sections above for specific optimizations.
A+Green HostingGreen (both)PASS
Green Hosting
Green (both)
Green (both)
Info::
Both hosting and CDN use renewable energy
Got: Hosting: Cloudflare, CDN: Cloudflare
Info::
Cloudflare: Verified by the Green Web Foundation
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 Cloudflare✓CDN Cloudflare✓
Cloudflare: Verified by the Green Web Foundation
Cloudflare: 100% renewable energy for global network since 2019
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight99% cachedPASS
Repeat Visit Weight
99% cached
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 30 KB (vs 4842 KB first visit). 129 of 132 resources are served from browser cache, saving 1.11g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 1.12g)
First visit
4842 KB
Repeat visit
30 KB
99% reduction on repeat visits
Saving 1.11g CO2 per returning visitor
129 resources served from cache · 3 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: Cloudflare
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.