Glossary
CO₂-Kostenaufteilung
CO₂-Kostenaufteilung: The CO₂-Kostenaufteilung (German for CO₂ cost allocation) sets how landlords and tenants in Germany share the CO₂ price on heating oil, natural gas and coal. Under the CO2KostAufG, the worse the building, the higher the landlord's share, up to 95 %.
What is the CO₂-Kostenaufteilung?
Since 2023 tenants in Germany no longer pay the CO₂ price on heating oil, natural gas and coal alone. The CO2KostAufG splits it with a tiered model, so landlords have a reason to modernise their buildings. Heat pump electricity and district heating are not covered.
The tiered model
| kg CO₂ per m² per year | Tenant | Landlord |
|---|---|---|
| under 12 | 100 % | 0 % |
| 12 to under 17 | 90 % | 10 % |
| 17 to under 22 | 80 % | 20 % |
| 22 to under 27 | 70 % | 30 % |
| 27 to under 32 | 60 % | 40 % |
| 32 to under 37 | 50 % | 50 % |
| 37 to under 42 | 40 % | 60 % |
| 42 to under 47 | 30 % | 70 % |
| 47 to under 52 | 20 % | 80 % |
| 52 or more | 5 % | 95 % |
New rules under the GModG
The Gebäudemodernisierungsgesetz added § 5a: for new fossil boilers under the Bio-Treppe, CO₂ price and network fees are split 50/50 from 2028, and the bio share from 2029. Small landlords have hardship rules (§ 5d). The Heating Cost Comparison Calculator shows the 20-year split between landlord and tenants in landlord mode.
This page is for information only and does not replace legal advice.
Frequently asked questions
It means 'CO₂ cost allocation': the legal split of the carbon price on heating fuels between landlord and tenant under the Kohlendioxidkostenaufteilungsgesetz (CO2KostAufG).
From the building's CO₂ emissions per square metre of living area per year. Below 12 kg the tenant pays everything; from 52 kg the landlord pays 95 %. In between the landlord's share rises in ten steps. The figures are on the fuel bill.
For gas and oil boilers installed after 29 July 2026, a fixed split applies from 2028: landlord and tenant each pay half of the CO₂ price and gas network fees. From 2029 they also split the extra cost of the bio share under the Bio-Treppe, up to a 30 % share (§ 5a CO2KostAufG).