Fasthosts vs IONOS: green hosting compared
Fasthosts and IONOS side by side: each one's Green Web Foundation listing, where its data centres are and how carbon-intensive those grids are, and the evidence it publishes. They are in alphabetical order: no host pays for its place.
The difference
Both are listed in the Green Web Foundation's directory of verified green providers.
Neither host's listed countries all have lower-carbon grids than the other's. Across both, their countries' grid averages run from 41 gCO2e/kWh in France (2025) to 384 gCO2e/kWh in the United States (2025), so which grid your site runs on depends on the region you choose.
On the listing and the grids, the evidence here does not separate them.
These are the facts we can show, not a verdict on which is greener: the listing, the grids and each company's own claims measure different things, and none of them measures your website. Each host's full page has every quote and source.
Each dot is a country where the host lists data centres, placed by that country's grid average. Fasthosts, listed in the Green Web Foundation's directory: 1 country, 218 gCO2e/kWh in the United Kingdom. IONOS, listed in the Green Web Foundation's directory: 5 countries, from 41 gCO2e/kWh in France to 384 in the United States.
Show the data as a table
| Country | Grid average, gCO2e/kWh | Year | Fasthosts | IONOS |
|---|---|---|---|---|
| France | 41 | 2025 | No | Yes |
| Spain | 153 | 2025 | No | Yes |
| United Kingdom | 218 | 2025 | Yes | Yes |
| Germany | 334 | 2025 | No | Yes |
| United States | 384 | 2025 | No | Yes |
Fasthosts
- Green Web Foundation
Listed in the Green Web Foundation's directory of verified green providers, checked 17 October 2026.
GWF lists it as “Fasthosts” (provider 1282).
GWF does not publish when a provider was last verified. Providers verified before October 2026 are reassessed under its new criteria, which no longer accept offsets, at their next reverification.
- Data centres
United Kingdom
Two UK data centres, in Worcester and London.
- Grid average where they are
- 218 gCO2e/kWh in the United Kingdom (2025).
- Fasthosts's own evidence
- Data centres Undated
- Our new bigger and better data centre 21 May 2024
- IONOS Group Sustainability Report 2025 Undated
- Evidence checked
- 16 October 2026
IONOS
- Green Web Foundation
Listed in the Green Web Foundation's directory of verified green providers, checked 17 October 2026.
GWF lists it as “IONOS SE” (provider 564).
GWF does not publish when a provider was last verified. Providers verified before October 2026 are reassessed under its new criteria, which no longer accept offsets, at their next reverification.
- Data centres
Germany, France, United Kingdom, Spain and United States
IONOS's own data centres and rented space in other companies' data centres; its pages do not say which hosting runs where.
- Grid average where they are
- Across the listed countries, from 41 gCO2e/kWh in France (2025) to 384 gCO2e/kWh in the United States (2025).
- IONOS's own evidence
- Evidence checked
- 16 October 2026
Grid figures: Ember, Yearly electricity data (2026), CC BY 4.0. Listing data from the Green Web Foundation's Green Web Dataset, made available under the Open Database License (ODbL).