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CO2 Cost Split Calculator 2026

Calculate the CO2 cost split for your apartment under Germany's CO2KostAufG. Since 2023, CO2 heating costs are shared between tenant and landlord — the worse the building's energy efficiency, the more the landlord pays. Enter your heating consumption and see the split instantly.

Found in your utility bill (Nebenkostenabrechnung)

How the CO2 Cost Sharing Act works

Since January 1, 2023, Germany's CO2 Cost Sharing Act (CO2KostAufG) applies to all residential buildings. CO2 costs from heating and hot water are split between tenant and landlord using a 10-step model.

The principle: The worse a building's energy efficiency (= higher CO2 emissions per m²), the more the landlord pays. This incentivizes landlords to invest in energy-efficient renovations.

The 10-step model explained

The split is based on CO2 emissions per square meter of living space per year:

  • Step 1 (< 12 kg CO2/m²): 100% tenant, 0% landlord — very energy-efficient
  • Steps 2-5 (12-32 kg CO2/m²): Gradually shifts toward the landlord
  • Steps 6-9 (32-52 kg CO2/m²): Landlord bears the majority
  • Step 10 (> 52 kg CO2/m²): 5% tenant, 95% landlord — urgent renovation needed

Where to find your heating consumption

Your annual heating consumption is listed in the Nebenkostenabrechnung (utility bill) from your landlord or directly from your energy provider. Pay attention to the unit: Gas and district heating are measured in kWh, heating oil in liters.

CO2 price trajectory: 2024-2030

The CO2 price increases step by step:

  • 2024: €45 per tonne
  • 2025: €50 per tonne
  • 2026: €55 per tonne (lower bound of €55-65 corridor)
  • From 2027: Transition to EU Emissions Trading System (EU ETS2) — market price

Legal basis: CO2-Kostenaufteilungsgesetz (CO2KostAufG)

📖 Related Article

CO2 cost allocation explained: the 10-step model, examples, and what tenants need to know.

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Frequently Asked Questions

Where do I find my heating consumption? ▼

Your annual heating consumption is listed in your utility bill (Nebenkostenabrechnung) from your landlord or directly from your energy provider. Look for kWh (gas, district heating) or liters (oil).

Does this apply to all rental properties in Germany? ▼

Yes, since January 1, 2023, the CO2 Cost Sharing Act (CO2KostAufG) applies to all residential buildings in Germany. Your landlord must show the cost split in your utility bill.

What if my landlord doesn't split the CO2 costs? ▼

Your landlord is legally required to split CO2 costs using the 10-step model. If they fail to do so, you can reduce the full CO2 cost charge by 50%. Notify your landlord in writing about the CO2KostAufG.

Will CO2 prices keep rising? ▼

Yes. The CO2 price is at €55 per tonne in 2026. From 2027, the national price will transition to the EU Emissions Trading System (EU ETS2), which is expected to push prices higher.

How can I reduce my CO2 costs? ▼

As a tenant: heat consciously, use thermostats, ventilate properly. As a landlord: improve insulation, modernize heating, or switch to heat pumps — this lowers the CO2 step and your cost share.