https://harpercollins.com
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
2
REVIEW
1
PASS
3
INFO
0
Checks
63 PASS 1 REVIEW 2 FIX
FCO2 Per Page LoadAction1.54g CO2 per viewFIX
CO2 Per Page Load
Action1.54g CO2 per view
1.54g CO2 per view
Warning::
1.54g CO2 per page view
This page transfers 6.5 MB, producing an estimated 1.54g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.04g, network 0.32g, end-user device 1.18g.
Got: 1.54g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 184.9 kg CO2/year
With 10,000 page views per month, this page would generate approximately 184.9 kg of CO2 annually — equivalent to charging 23106 smartphones.
Info::
Green hosting reduces data center emissions
1.54g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 24% of websites
Sustainable Web Design model v4 · Page size: 6.5 MB
Your site
1.54g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.04g
Network
0.32g
End-user device
1.18g
At 10,000 monthly views: Monthly: 15.4 kg · Annual: 184.9 kg · ≈ 23106 smartphone charges
FCarbon BudgetAction76th percentileFIX
Carbon Budget
Action76th percentile
76th percentile
Warning::
1.54g CO2 — above the median website (0.60g)
Heavier than an estimated 24% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 76th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
1.54g
76th percentile
Cleaner than 24% of websites
✗ Above the median website
vs Median 157% more
vs Target 208% more
BTransfer Efficiency84% efficientREVIEW
Transfer Efficiency
84% efficient
84% efficient
Info::
Transfer efficiency: 84%
An estimated 1041 KB (16%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 1041 KB of unused JavaScript. This wasted data produces 0.24g of unnecessary CO2 per page view.
Total waste: 1041 KB (16% of page weight)
Unused JS 1041 KB
0.24g unnecessary CO2 per visit
Actual transfer 6664 KB
Theoretical minimum 5623 KB
Potential savings 1041 KB (0.24g 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 Weight97% cachedPASS
Repeat Visit Weight
97% cached
97% cached
Info::
97% reduction on repeat visits
Returning visitors download only 210 KB (vs 6664 KB first visit). 577 of 589 resources are served from browser cache, saving 1.49g CO2 per repeat visit.
Info::
Repeat visit: 0.05g CO2 (first visit: 1.54g)
First visit
6664 KB
Repeat visit
210 KB
97% reduction on repeat visits
Saving 1.49g CO2 per returning visitor
577 resources served from cache · 12 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.