CO₂ costs

CO₂ cost allocation: what landlords and tenants each pay

11 September 2026MEVIO editorial teamReading time 8 minutes

Key points at a glance

Since 2023, landlords have borne part of the CO₂ costs of heating — governed by the Carbon Dioxide Cost Allocation Act (Kohlendioxidkostenaufteilungsgesetz, CO2KostAufG).
For residential buildings, the decisive factor is CO₂ emissions per m² of living space: the poorer the building, the higher the landlord’s share (0 to 95%).
For non-residential buildings, costs are currently split 50:50.
The split belongs in the heating cost statement. If it is missing, tenants may reduce their share of the heating costs by 3%.
In an owners’ association (Wohnungseigentümergemeinschaft, WEG), the obligation lies with the letting owner — who needs the CO₂ details from the heating cost statement for this.

Anyone who heats with natural gas or heating oil has been paying a CO₂ price since 2021. It is included in the fuel price and has risen considerably over the years. For a long time, it was passed on in full to the tenant via the heating cost statement. Since 2023, this has changed: the landlord bears a share — and the more CO₂ their building emits per square metre, the larger that share.

The idea behind it is simple. The tenant influences their heating behaviour, the landlord the condition of the building envelope and the heating system. Anyone with poor insulation or an old heating system should contribute to the CO₂ price and so have an incentive to modernise.

Legal basis

Carbon Dioxide Cost Allocation Act (CO2KostAufG)

In force since 1 January 2023. Applies to billing periods from that date and to all buildings in which fuels subject to a CO₂ price under the Fuel Emissions Trading Act (Brennstoffemissionshandelsgesetz, BEHG) are burned — mainly natural gas and heating oil, including via district heating.

§ 3: Fuel and heat suppliers must state the CO₂ quantity and CO₂ costs on the invoice.
§ 5 with annex: Residential buildings: split according to the ten-tier model, measured by CO₂ emissions per m² of living space.
§ 6: Tenants with their own supply contract claim back the landlord’s share within twelve months.
§ 7: The landlord determines the split in the heating cost statement. If it is missing, the tenant may reduce their share of the heating costs by 3%.
§ 8: Non-residential buildings: landlord and tenant each bear half of the CO₂ costs.
§ 9: If public-law requirements such as listed-building protection prevent energy-efficiency refurbishment, the landlord’s share is reduced.

Text of the Act on gesetze-im-internet.de (in German)

The tier model for residential buildings

At the heart of the Act is a model with ten tiers. The decisive factor is how much CO₂ the building emitted per square metre of living space in the billing year. A well-insulated house with efficient heating is in the lower tiers — there, the tenant bears all or almost all of the CO₂ costs. An unrefurbished building ends up at the top, and the landlord pays up to 95 per cent.

The tier model for residential buildingsThe building’s CO₂ emissions in kg per m² of living space per year — and who bears which share of the CO₂ costs

Tenant’s shareLandlord’s share

Tier 1
under 12 kgTenant 100 per cent, landlord 0 per cent
Tier 2
12 to under 17 kgTenant 90 per cent, landlord 10 per cent
Tier 3
17 to under 22 kgTenant 80 per cent, landlord 20 per cent
Tier 4
22 to under 27 kgTenant 70 per cent, landlord 30 per cent
Tier 5
27 to under 32 kgTenant 60 per cent, landlord 40 per cent — tier of the worked example
Tier 6
32 to under 37 kgTenant 50 per cent, landlord 50 per cent
Tier 7
37 to under 42 kgTenant 40 per cent, landlord 60 per cent
Tier 8
42 to under 47 kgTenant 30 per cent, landlord 70 per cent
Tier 9
47 to under 52 kgTenant 20 per cent, landlord 80 per cent
Tier 10
52 and above kgTenant 5 per cent, landlord 95 per cent

Tier 2: landlord 10%. Tier 10: tenant 5%, landlord 95%. The tier of the worked example further below is highlighted. Source: annex to the CO2KostAufG.

The classification is made anew every year. A cold winter can therefore push a building up one tier, while refurbishment or a new heating system can move it down several tiers.

How the split is calculated

The calculation itself is straightforward. The key figures are provided by the supplier: on the fuel or heat invoice, it must state how much CO₂ was produced and what CO₂ costs are included.

How the split works — in four steps

Supplier’s invoiceThe fuel or heat supplier states the CO₂ quantity and CO₂ costs.
Determine CO₂ per m²Total CO₂ quantity divided by the living space of the building.
Assign the tierThe value per m² determines one of the ten tiers and thus the ratio.
Split in the statementThe landlord’s share is deducted in the heating cost statement.

Worked example: apartment building with gas central heatingSimplified sample calculation

Living space of the building: 600 m²
Natural gas consumption per year: 90,000 kWh
CO₂ emissions (factor 0.201 kg/kWh): 18,090 kg
CO₂ per m² of living space: 30.2 kg → tier 5
CO₂ costs (€55 per tonne): €994.95

Tenant’s shareLandlord’s share

Tenants: €596.97Landlord: €397.98

In practice, the CO₂ quantity and the CO₂ costs stated by the supplier on its invoice are decisive. The CO₂ price under the BEHG lies within a corridor of €55 to €65 per tonne in 2026.

In the example, with around 30 kg CO₂ per square metre, the building is in tier 5. The landlord bears 40 per cent of the CO₂ costs, i.e. €397.98 per year. They may not pass this amount on to the tenants; it is deducted from the recoverable costs in the heating cost statement.

Non-residential buildings: 50:50 split

For offices, medical practices, shops and other non-residential buildings, there is currently no tier model. Landlord and tenant each bear half of the CO₂ costs.

Special cases that are common in practice

Tenants with their own gas contract. With gas storey heating or individual heating, the tenant often settles directly with the supplier. In that case, they first pay the CO₂ costs in full and then claim back the landlord’s share — within twelve months of receiving the supplier’s invoice.

Listed-building protection and similar requirements. If a building may not be refurbished for energy efficiency, or only to a limited extent, for public-law reasons — for example because of listed-building or conservation-area protection — the landlord’s share is reduced. The landlord must provide evidence of the restriction.

Heating without a CO₂ price. Heat pumps, wood pellets or solar thermal systems do not cause CO₂ costs within the meaning of the Act. In that case, there is simply nothing to split.

What this means for owners’ associations

The association of flat owners is not the landlord. The obligation to split the costs lies with the individual owner who lets their flat. However, they can only fulfil it if they receive the necessary figures — and these are produced in the association’s heating cost statement.

For each let unit, the statement should therefore contain:

the CO₂ quantity and the CO₂ costs of the building,
the living space used as a basis and the value per m²,
the resulting tier with the split ratio,
the unit’s share of the CO₂ costs, broken down by tenant and landlord.

If these details are missing, every letting owner has to do the calculation themselves — and risks the three per cent reduction if they do not. For the property management, this is a point to clarify with its metering service before the next statement is prepared.

Heating cost statement with CO₂ split

Send us the number of residential and commercial units and your last heating cost statement. You will receive a quote with a comparison against your current costs.

Request a quote More articles

This article is intended as general guidance and does not replace legal advice in individual cases. As of: September 2026.

Frequently asked questions

CO₂ cost allocation — quick answers

Since when have CO₂ costs been split between landlord and tenant?

Since 1 January 2023. The Carbon Dioxide Cost Allocation Act (Kohlendioxidkostenaufteilungsgesetz, CO2KostAufG) applies to all billing periods beginning on or after that date. Before that, tenants bore the CO₂ costs alone as part of the heating costs.

How is the landlord’s share calculated for residential buildings?

According to a tier model with ten tiers. The decisive factor is the building’s annual CO₂ emissions per square metre of living space. The poorer the energy performance, the higher the landlord’s share: from 0 per cent below 12 kg CO₂/m² to 95 per cent from 52 kg CO₂/m².

What applies to commercial and other non-residential buildings?

For non-residential buildings, the law currently provides for a 50:50 split: landlord and tenant each bear half of the CO₂ costs.

What happens if the landlord does not split the CO₂ costs?

If the heating cost statement does not show the share, the tenant may reduce their share of the heating costs by 3 per cent. Irrespective of this, the entitlement to the correct split remains.

And if the tenant settles their gas storey heating directly with the supplier?

In that case, the tenant first settles the CO₂ costs with the supplier themselves and then claims the landlord’s share back from the landlord — within twelve months of receiving the supplier’s invoice.

How does this work in an owners’ association (WEG)?

The association itself is not the landlord. The split is the responsibility of the individual letting owner towards their tenant. To be able to carry it out, they need from the heating cost statement the building’s CO₂ quantity, the living space, the tier classification and the share of CO₂ costs attributable to their unit.