Skip to content
https://aalto.fi

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
87
GRADE
B
FIX
0
REVIEW
2
PASS
4
INFO
0
Device:
Mobile Desktop
Checks
6
4 PASS 2 REVIEW
B
Transfer Efficiency
85% efficient
REVIEW
85% efficient
Info::
Transfer efficiency: 85%
An estimated 202 KB (15%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 202 KB of unused JavaScript. This wasted data produces 0.05g of unnecessary CO2 per page view.
85% efficient

Total waste: 202 KB (15% of page weight)

Unused JS 202 KB

0.05g unnecessary CO2 per visit

Actual transfer 1373 KB
Theoretical minimum 1171 KB
Potential savings 202 KB (0.05g 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
CO2 Per Page Load
0.32g CO2 per view
PASS
0.32g CO2 per view
Info::
0.32g CO2 per page view
This page transfers 1.3 MB, producing an estimated 0.32g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.07g, end-user device 0.24g.
Got: 0.32g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 38.1 kg CO2/year
With 10,000 page views per month, this page would generate approximately 38.1 kg of CO2 annually — equivalent to charging 4762 smartphones.
Info::
Green hosting reduces data center emissions

0.32g

Carbon Footprint per page view

✓ Below sustainability target (0.50g)

Cleaner than 79% of websites

Sustainable Web Design model v4 · Page size: 1.3 MB

Your site
0.32g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.01g
Network
0.07g
End-user device
0.24g
At 10,000 monthly views: Monthly: 3.2 kg · Annual: 38.1 kg · ≈ 4762 smartphone charges
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
98% cached
PASS
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 25 KB (vs 1373 KB first visit). 55 of 57 resources are served from browser cache, saving 0.31g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.32g)
First visit
1373 KB
Repeat visit
25 KB

98% reduction on repeat visits

Saving 0.31g CO2 per returning visitor

55 resources served from cache · 2 resources re-downloaded

A
Carbon Budget
21th percentile
PASS
21th percentile
Info::
0.32g CO2 — below the sustainability target of 0.50g
Cleaner than an estimated 79% of websites analyzed. This page meets the Web Sustainability Guidelines target.
Info::
Estimated 21th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.32g

21st percentile

Cleaner than 79% of websites

✓ Below the Web Sustainability Guidelines target

vs Median 47% cleaner ✓
vs Target 37% cleaner ✓
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback