CO2 costs in the 2024 heating cost statement: how landlords and tenants share them

Heating and hot water statements for 2024 are currently being prepared. If you heat with gas or heating oil, the CO2 costs must be split between landlord and tenant in these statements. The legal basis is the Carbon Dioxide Cost Allocation Act (Kohlendioxidkostenaufteilungsgesetz, CO2KostAufG). It applies to all billing periods beginning on or after 1 January 2023, so the 2024 statement is the second full round.

Where the figures come from

Fuel and heat suppliers must state on their invoices the emissions of the delivery in kilograms of CO2, the emission factor, the energy content and the CO2 cost component of the price (§ 3 CO2KostAufG). For deliveries in 2024, the fixed price under the Fuel Emissions Trading Act (Brennstoffemissionshandelsgesetz) was 45 euros per tonne of CO2; since January 2025 it has been 55 euros.

The tiered model for residential buildings

The landlord calculates the building's CO2 emissions per square metre of floor area per year and rounds to one decimal place. The value is then classified using the table in the annex to the Act. Below 12 kg of CO2 per square metre, the tenant bears the CO2 costs alone. The table has ten tiers, and the landlord's share increases with each one. At 32 to under 37 kg, the costs are split equally. From 52 kg, the landlord bears 95 per cent.

For non-residential buildings, an equal split applies until further notice (§ 8 CO2KostAufG). If listed building protection, a mandatory connection and use requirement or a conservation by-law prevents energy-efficient refurbishment, the landlord's share is halved (§ 9). The landlord must provide evidence of these circumstances.

What must be included in the statement

Under § 7 Abs. 3 CO2KostAufG, the heating cost statement must include the tenant's share of the CO2 costs, the classification of the building and the basis of calculation. If this information is missing, the tenant may reduce their share of the heating costs by 3 per cent (§ 7 Abs. 4).

In practice, this means: before sending, check whether the billing service provider has actually stated the classification and whether all fuel invoices for the period have been taken into account. If tenants heat their homes themselves, for example with a gas boiler serving their flat only, they must assert their claim for reimbursement against the landlord in text form within twelve months of their supplier's statement (§ 6 Abs. 2).

Addendum (November 2026): With the reform of the Building Energy Act (Gebäudeenergiegesetz) (BGBl. 2026 I Nr. 226), §§ 5a to 5d were added to the CO2KostAufG. They provide for an equal split of costs for certain newly installed heating systems under § 43 of the Building Modernisation Act (Gebäudemodernisierungsgesetz) from 2028. The tiered model for other residential buildings continues to apply unchanged. For 2026, a price corridor of 55 to 65 euros per tonne applies under the BEHG.