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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
1.20g CO2 per view
FIX
1.20g CO2 per view
Warning::
1.20g CO2 per page view
This page transfers 5.1 MB, producing an estimated 1.20g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.03g, network 0.25g, end-user device 0.92g.
Got: 1.20g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 143.7 kg CO2/year
With 10,000 page views per month, this page would generate approximately 143.7 kg of CO2 annually — equivalent to charging 17966 smartphones.
Info::
Green hosting reduces data center emissions

1.20g

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
1.20g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.03g
Network
0.25g
End-user device
0.92g
At 10,000 monthly views: Monthly: 12.0 kg · Annual: 143.7 kg · ≈ 17966 smartphone charges
D
Carbon Budget
Action
67th percentile
FIX
67th percentile
Warning::
1.20g 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

1.20g

67th percentile

Cleaner than 33% of websites

✗ Above the median website

vs Median 100% more
vs Target 140% more
B
Transfer Efficiency
86% efficient
REVIEW
86% efficient
Info::
Transfer efficiency: 86%
An estimated 736 KB (14%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 736 KB of unused JavaScript. This wasted data produces 0.17g of unnecessary CO2 per page view.
86% efficient

Total waste: 736 KB (14% of page weight)

Unused JS 736 KB

0.17g unnecessary CO2 per visit

Actual transfer 5181 KB
Theoretical minimum 4445 KB
Potential savings 736 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 5181 KB first visit). 151 of 153 resources are served from browser cache, saving 1.18g CO2 per repeat visit.
Info::
Repeat visit: 0.02g CO2 (first visit: 1.20g)
First visit
5181 KB
Repeat visit
72 KB

99% reduction on repeat visits

Saving 1.18g CO2 per returning visitor

151 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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