Since 1 January 2023, German landlords can no longer pass all carbon costs from oil, gas and district heating to tenants: the CO2KostAufG splits them according to the building's climate performance.
"The landlord bears the share of the carbon dioxide costs, as set out in the annex, resulting from the building's carbon dioxide emissions per square metre of living space per year."
— § 6 (1) CO2KostAufG (translated)
The ten-tier model
The worse the emissions record, the higher the landlord's share:
- < 12 kg CO₂/m²a → landlord 0% (efficient new builds)
- 12–17 kg → 10% · 17–22 kg → 20% · 22–27 kg → 30%
- 27–32 kg → 40% · 32–37 kg → 50% · 37–42 kg → 60%
- 42–47 kg → 70% · 47–52 kg → 80%
- ≥ 52 kg CO₂/m²a → landlord 95% (unrenovated old stock)
Putting it into practice
Fuel suppliers must state CO₂ volumes and costs on their invoices; the tier classification belongs in the heating statement. Landlords who simply omit the split face a tenant's right to cut heating costs by 3%.
The statute's message is deliberately economic: retrofitting lowers your own cost share. Our CO₂ calculator shows your tier in seconds.