This law impacts homeowners and renters. The former can still freely decide which heating system they want to install. Climate-friendly options such as heat pumps offer low operating costs and higher purchase costs. With fossil heating systems it is exactly the opposite. This is especially true because in the coming years CO2 prices and network fees will rise. In addition, the organic versions of natural gas and heating oil are more expensive than conventional materials.

What costs tenants have to bear

As a homeowner, you can calculate and weigh up the advantages and disadvantages of both options. But 53 percent of Germans do not own any real estate, but rather live in rent. The landlord decides what is used for heating. However, he only has to bear the financial consequences of his actions to a limited extent. Acquisition costs can be passed on to the tenants as modernization, as can the operating costs. This is what it means for you.

Purchase: The landlord can pay this

The following costs are due for the purchase:

• A classic gas heater usually costs 6,000 to 9,000 euros including installation.
  An H2-ready gas heater costs 9,000 to 12,000 euros.
• Oil heaters cost 6,000 to 9,000 euros plus 2,000 to 4,000 euros for the tank. In total, landlords pay between 8,000 and 13,000 euros.
• Heat pumps cost 15,000 to 40,000 euros. With government funding, the price drops to between 10,500 and 28,000 euros.

However, your landlord cannot simply pass these costs on to you. This is only possible with modernizations. However, if your landlord replaces an old gas heater with a new one, this does not count as such. So he has to bear the costs himself. Here are some examples:

• If your landlord replaces an old gas or oil heating system with a new gas or oil heating system, this usually applies not as modernization.
• If your landlord exchanges an old oil heating system for a new oil heating system that will be operated with organic heating oil from 2029, this also usually applies not as modernization.
• If your landlord replaces an old gas heater with a new H2-ready gas heater, this usually applies initially not as modernization. But if he can prove that your municipality will have a hydrogen network in a few years, things may look different.
• If your landlord exchanges an old gas or oil heating system for a heat pump, this usually applies as modernization. The same generally applies when installing a pellet heater or another type of heating that runs on renewable energy.
• If your landlord exchanges an old heat pump for a new heat pump, does that only count as modernization, if the new heating is more effective. This could be measured, for example, using the annual performance factor (JAZ).

These costs can be passed on

But even with modernizations, the full costs cannot be distributed among the tenants. The state only allows this for the cost of the added value of a new system. The landlord is allowed to add eight percent of this per year to your rent.

It is calculated like this: The starting point is the costs of the new heating system. The landlord must deduct all funding from this. He then has to deduct the costs that a heating system that was comparable to the old one would have cost. The remaining costs can now be passed on to the tenants.

Calculation example for a new heating system

The old gas heater in your apartment building is giving up the ghost. The landlord is therefore installing a modern heat pump.

• Costs including installation 30,000 euros.
• 30 percent of the costs are funded by the state, i.e. 9,000 euros. He has to deduct this from the price, so there are still 21,000 euros left.
• A new gas heater would have cost 7,500 euros.
• This amount is also deducted, leaving 13,500 euros. This now corresponds to the value of modernization.
• The landlord can now add eight percent of this to the annual rent. That would be 1080 euros. Your rent would therefore increase by 90 euros per month.

A second example:

The landlord is replacing the old gas heating system with an H2-ready gas heating system. Because your municipality will operate a hydrogen network from 2028, you can pass on the costs.

• The new heating costs 10,500 euros, the old one would have cost 7,500 euros. There is no funding.
• The modernization costs are therefore 3000 euros.
• Eight percent of that would be 240 euros per year. Your rent would increase by 20 euros per month.

This is what happens with the additional costs

The Operating costs You pay for your heating via the utility bill. The amount depends on consumption. If we assume a family with two children, it is around 20,000 kilowatt hours of heating energy per year. To do this you either need the same amount of natural gas, 2000 liters of heating oil or 4000 to 6700 kilowatt hours of electricity for a heat pump.

The costs for this vary. Natural gas of this magnitude currently costs you around 2,000 euros per year, heating oil 2,150 euros and electricity between 1,024 and 1,707 euros. Through the rising CO2 price and increasing network fees, the costs for all three resources will rise. The following numbers are estimates from the ADAC and the Fraunhofer Institute.

• The price of natural gas The CO2 price will increase by 0.3 to 3.2 cents per kilowatt hour, and network fees will increase by 5 cents. Calculated using average values, 20,000 kilowatt hours of natural gas will cost 1,350 euros more per year in 2030 than it does today.
• The price of heating oil will increase by an average of 23.9 cents per liter due to the CO2 price. There are no network fees here. For 2000 liters of heating oil you pay 478 euros more than today. Organic heating oil, which would be mandatory from 2029, is around ten percent more expensive. In total, your costs increase by 526 euros.
• At Electricity The CO2 price only plays an indirect role. Grid fees, on the other hand, are expected to rise by 7 cents per kilowatt hour. At 4,000 to 6,700 kilowatt hours for a heat pump that would be between 280 and 469 euros more per year.

This is how much you pay extra as a tenant

Combining both cost points results in the total burden for tenants. The exact values ​​can be found in the table. However, some trends are recognizable. The most favorable conditions are those whose landlord heats with an effective heat pump. Switching from there to any other type of heating will be expensive. Conversely, switching from any other type of heating to an effective heat pump is also expensive for tenants.

Heat pumps become expensive for tenants

This is due to their high costs of an average of 30,000 euros. Although landlords receive the basic subsidy of 30 percent, they rarely receive the 30 percent subsidy for people with low incomes. Since we assume that the old heater is broken, the speed bonus of 20 percent is also eliminated. A good heat pump costs 21,000 euros, of which at least half can be passed on to the tenants.

The better option is to install a less efficient heat pump if you currently heat with oil or gas. It only costs around half as much. Together with the lower operating costs, this always pays off advantageously for the tenants.