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https://rnz.co.nz

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
73
GRADE
C
FIX
2
REVIEW
2
PASS
2
INFO
0
Device:
Mobile Desktop
Checks
6
2 PASS 2 REVIEW 2 FIX
D
CO2 Per Page Load
Action
1.21g CO2 per view
FIX
1.21g CO2 per view
Warning::
1.21g CO2 per page view
This page transfers 5.1 MB, producing an estimated 1.21g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.03g, network 0.25g, end-user device 0.93g.
Got: 1.21g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 145.7 kg CO2/year
With 10,000 page views per month, this page would generate approximately 145.7 kg of CO2 annually — equivalent to charging 18207 smartphones.
Info::
Green hosting reduces data center emissions

1.21g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 33% of websites

Sustainable Web Design model v4 · Page size: 5.1 MB

Your site
1.21g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.03g
Network
0.25g
End-user device
0.93g
At 10,000 monthly views: Monthly: 12.1 kg · Annual: 145.7 kg · ≈ 18207 smartphone charges
D
Carbon Budget
Action
67th percentile
FIX
67th percentile
Warning::
1.21g CO2 — above the median website (0.60g)
Heavier than an estimated 33% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 67th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

1.21g

67th percentile

Cleaner than 33% of websites

✗ Above the median website

vs Median 102% more
vs Target 143% more
B
Transfer Efficiency
86% efficient
REVIEW
86% efficient
Info::
Transfer efficiency: 86%
An estimated 721 KB (14%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 721 KB of unused JavaScript. This wasted data produces 0.17g of unnecessary CO2 per page view.
86% efficient

Total waste: 721 KB (14% of page weight)

Unused JS 721 KB

0.17g unnecessary CO2 per visit

Actual transfer 5251 KB
Theoretical minimum 4529 KB
Potential savings 721 KB (0.17g CO2)

See Deep Analysis sections above for specific optimizations.

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A
Green Hosting
Green (cdn)
PASS
Green (cdn)
Info::
Fastly CDN uses renewable energy
Since most traffic is served through the CDN, the majority of data transfer energy is renewable.
Info::
Fastly: 100% renewable energy for edge network
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 Fastly✓

Fastly: 100% renewable energy for edge network

Based on known provider commitments. Verify at thegreenwebfoundation.org

A+
Repeat Visit Weight
99% cached
PASS
99% cached
Info::
99% reduction on repeat visits
Returning visitors download only 72 KB (vs 5251 KB first visit). 168 of 170 resources are served from browser cache, saving 1.20g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 1.21g)
First visit
5251 KB
Repeat visit
72 KB

99% reduction on repeat visits

Saving 1.20g CO2 per returning visitor

168 resources served from cache · 2 resources re-downloaded

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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