In Germany, CO2 costs for heating a rented flat are not divided in a flat way. The Carbon Dioxide Cost Sharing Act (Kohlendioxidkostenaufteilungsgesetz, CO2KostAufG) sets out which share the landlord and which share the tenant bears. The decisive factor is how much carbon dioxide the building emits per square metre of living space per year.
Short answer: The CO2 Cost Sharing Act splits CO2 costs according to emissions per square metre of living space. Below 12 kilograms of CO2 per square metre and year the tenant bears 100 percent, and from 52 kilograms the landlord bears 95 percent. The landlord must show the tenant share in the statement. Last updated: November 2026, based on pages retrieved on 2 November 2026.
The most important points in brief
- The split depends on the carbon dioxide emitted by the building or flat per square metre of living space and year.
- The banding model in the annex to the act has ten bands, running from under 12 to 52 kilograms of CO2 per square metre.
- The higher the emissions, the larger the share borne by the landlord.
- The landlord must show the tenant share, the classification and the calculation basis in the heating cost statement.
- If the information is missing or the share is not determined, the tenant may reduce his or her share of the heating costs by 3 percent.
Which bands apply under the law?
The annex to sections 5 to 7 of the act assigns a fixed distribution key to each emissions value. The table reproduces the ten bands as they appeared on the page of the Federal Office of Justice retrieved on 2 November 2026. The flat is classified according to its emissions per square metre of living space per year.
| Band | CO2 emissions in kg per m² and year | Tenant share | Landlord share |
|---|---|---|---|
| 1 | under 12 | 100 % | 0 % |
| 2 | 12 to under 17 | 90 % | 10 % |
| 3 | 17 to under 22 | 80 % | 20 % |
| 4 | 22 to under 27 | 70 % | 30 % |
| 5 | 27 to under 32 | 60 % | 40 % |
| 6 | 32 to under 37 | 50 % | 50 % |
| 7 | 37 to under 42 | 40 % | 60 % |
| 8 | 42 to under 47 | 30 % | 70 % |
| 9 | 47 to under 52 | 20 % | 80 % |
| 10 | 52 and above | 5 % | 95 % |
The table shows a clear pattern. The weaker the energy balance of the building, the more the act relieves the tenant and burdens the landlord. In a well-insulated building the tenant share is therefore the larger part, while in a poorly insulated older building the landlord bears the larger part.
What does a worked example look like?
Assumption: the CO2 costs for the building total 1,000 euros in the billing year, and the building falls into band 6 with 32 to under 37 kilograms of CO2 per square metre. The calculation illustrates the mechanism and does not replace a check of the actual statement.
- Tenant share: 50 percent of 1,000 euros gives 500 euros.
- Landlord share: 50 percent of 1,000 euros gives 500 euros.
- Comparison with band 10: there the tenant bears only 5 percent, which is 50 euros, and the landlord bears 950 euros.
The example shows how strongly the classification shifts the amount. The same total costs can lead to very different shares for two tenants, depending on how the building is classified. For this reason the classification in the statement should always be checked.
What duties does the landlord have?
The landlord determines the tenant share by calculating the carbon dioxide emissions and the carbon dioxide costs and deducting the share that falls on the landlord. The allocation to the individual tenant then follows the agreement on heating and hot water costs and the Heating Costs Ordinance. Section 7 (1) of the act sets this out.
Under section 7 (3), the landlord must show in the heating cost statement the tenant share, the classification of the building or flat and the calculation basis. If this information is missing or the share is not determined, the tenant may under section 7 (4) reduce his or her share of the heating costs by 3 percent.
Are there exceptions?
Yes. Under section 7 (2), in residential buildings with at most two flats, one of which the landlord lives in, the tenant bears his or her share according to the agreed heating cost method. Anyone living in such a house should therefore first check which rule applies to their flat.
Why the band matters so much
The band decides a considerable part of the statement. A building classified wrongly can lead to a tenant share that does not match the actual emissions. It is therefore not enough to accept the band shown without question. The energy certificate of a building gives a first impression of its energy demand, but it does not replace the figures in the heating cost statement itself.
The split of CO2 costs also does not change the total of the heating costs. Tenants should therefore check separately whether the consumption values, the allocation keys and the billing period are correct. The CO2 band is only one part of the check, and all parts together give a complete picture of the statement.
Frequently asked questions
How do I find out the band of my flat?
The band follows from the emissions of the building per square metre of living space and year. The landlord must show the classification in the statement. If you cannot find it, ask, and refer to the disclosure under section 7 (3).
Can the landlord choose the band freely?
The band follows from the emissions under the annex to the act. The landlord must disclose the classification and the calculation basis. The annex does not provide for a free choice of band.
What happens if the statement lacks the information?
Then the tenant may reduce his or her share of the heating costs by 3 percent. Before doing so, a written request to the landlord is worthwhile, so that the missing information can be supplied.
Does the split also apply to students in halls of residence?
That depends on the contract and on the building. Whether a hall of residence falls under the act and how its statement is structured should be asked of the student services organisation or the operator of the hall.
Must the landlord show the CO2 share separately?
Under section 7 (3), the landlord must show the tenant share, the classification and the calculation basis in the heating cost statement. The retrieved version of the act does not prescribe in detail how the information must be laid out on the statement. What matters is that the figures can be followed.
What you can do now
- Look in your heating cost statement for the tenant share, the classification of the building and the calculation basis.
- Compare the band shown with the table and check whether the share is plausible.
- Request missing information from the landlord in writing and set a reasonable deadline.
- Only if the information is still missing after that does a reduction of 3 percent come into consideration.
Related reading
- Climate, Energy and Costs 2027: The overview for tenants and students
- CO2-Preis 2027: What the price corridor means for heating
- Heizkostenabrechnung prüfen: Deadlines, allocation and typical errors
- Modernisierungsumlage nach Heizungstausch: Was der Vermieter darf
Sources: Annex to sections 5 to 7 CO2KostAufG, banding model (Federal Office of Justice, retrieved 2 November 2026) and section 7 CO2KostAufG, settlement (Federal Office of Justice, retrieved 2 November 2026).
Last updated: November 2026. This guide is general information, not individual advice.
