Heat pumps in apartment buildings, how does it work?

Heat pumps offer an attractive option as a heating system and are a good alternative to heating systems that use fossil fuels. But not everyone owns their own home so that they can easily and quickly switch from oil and gas heating systems to a heat pump. Around 70% of Germans live in apartment buildings and are wondering whether they can install a heat pump there. How does that work in such a case?

Decentralized heat pumps in apartment buildings: an efficient solution for heating and hot water

Heat pumps are often used for single-family homes, but they can also be efficient for multi-family homes.

What are decentralized heat pumps?

Decentralized heat pumps are small heat pumps that are installed in every apartment in an apartment building, i.e. comparable to floor heating. Each apartment has its own heat pump, which is used for heating and hot water.

Benefits of decentralized heat pumps

Decentralized heat pumps increase energy efficiency by minimizing heat losses. Each tenant can independently control the temperature in their apartment, which increases living comfort. Maintaining these heat pumps is easier as they are installed in every single apartment.

Each apartment also has its own hot water tank, which can be switched off temporarily to save energy. Heat pumps use environmental heat, are environmentally friendly and have low operating costs, making the investment quickly worthwhile.

Central heat pumps for an apartment building

A central heat pump for the entire apartment building is also an option. Of course, all parties in the apartment building must agree and agree to a heat pump. But is it worth it? Which is better: decentralized systems or centralized systems?

That is not easy to answer, because it depends on the current supply and also the available space. We have already explained the advantages of decentralized heat pumps in the previous section: They are easier to maintain, control and even bill.

Centralized heat pump systems offer several advantages over decentralized solutions with separate heat pumps per residential unit:

• Lower investment costs thanks to a single large plant
• Lower overall maintenance and repair
• Space-saving solution as only one technical room is required

However, the distribution lines for heat transfer to individual apartments are longer, which can lead to higher heat losses. In addition, a heat pump for an apartment building must also do more than the individual systems in the decentralized solution.

Cost of a heat pump in an apartment building

The decision to install a heat pump in an apartment building includes taking into account both purchase costs and long-term operating costs.

Compared to single-family homes, the costs for a heat pump in an apartment building are higher due to the larger dimensions and the higher demand for heating capacity. The purchase costs can still be based on the purchase costs of heat pumps for a single-family house, for example, if you consider the larger dimension. The purchase costs also depend, of course, on whether you opt for a centralized or a decentralized system.

Examples of acquisition costs:

• In a single-family home, the purchase costs of an air heat pump (brine-water heat pump) are typically between 8,000 and 15,000 euros. For an apartment building, the costs are correspondingly higher, although the installation costs of 3,000 to 6,000 euros can significantly exceed, particularly in the case of a decentralized heat pump system.*
• Using geothermal energy requires a higher investment. A geothermal heat pump in an apartment building can cost between 10,000 and 12,000 euros. However, the complex installation costs can amount to up to 20,000 euros, which increases the total cost of a geothermal heat pump in an apartment building.*

If a heat pump can be operated independently of fossil fuels or a hybrid system is used, costs fall accordingly. In order to increase the efficiency of a heat pump, there are a few factors that should be considered, you can find out more about them in our last blog post: Improving energy efficiency through renewable energy.

*Possible subsidies are already accounted for here.

Operating costs of a heat pump in an apartment building

The costs for a heat pump in an apartment building vary depending on the type of heat pump, size of the building, use, maintenance and wear. It is important to consider the long-term savings and energy efficiency of a heat pump to make an informed decision. By combining heat pumps with renewable energy such as PV systems including batteries, you can not only improve the environmental balance, but also save money in the long term.

In a residential complex with 1,000 square meters of living space, a heat pump consumes an average of around 39 kWh per square meter and year, which amounts to a total of around 39,000 kWh per year.

The electricity costs of 41.98 cents per kilowatt hour in August 2022 result in annual electricity costs of around 16,372€ for operating the heat pump. Costs can be reduced by installing a solar system and using a tenant electricity model.

Who bears the costs of a heat pump in an apartment building?

In a condominium owners' association (WEG), in principle, all owners bear the costs of structural changes, such as the installation of a heat pump, in accordance with the ratio of their co-ownership shares.

It's different with a rental house. In this case, the landlord bears the costs of installing a heat pump system. Operating costs are transferred to tenants on a pro rata basis via the heating bill.

Heating bill for an apartment building with heat pumps

The heating bill for an apartment building with heat pumps is a complex issue.

In principle, a heat pump in an apartment building can be billed with or without a consumption-based heating bill. According to Section 11 No. 3 HeizkostenV, the obligations to measure consumption and consumption-based heating bill for heat and hot water billing for heat pumps can be excluded.

A building is mainly supplied with heat from renewable sources when this is more than 50%. If a building is mainly supplied with a heat pump, it is advisable to agree on a warm rent or a flat rate based on the living space.

The total costs of the heating system are allocated to heating and hot water production. The thermal energy input of a heat pump into the heating system must be known. To do this, electricity meters and heat meters must be installed directly on the heat pump.

As with all other heating systems, at least 50%, but not more than 70% of the heating and hot water costs must be distributed over the actual consumption per individual residential unit.

A consumption-based calculation of the operating costs of heat pumps is definitely recommended. It is recommended to install qualified measurement equipment to ensure optimum operation of the heat pump. Anyone who saves here is saving at the wrong end and will have to spend several times the costs through additional expenses.

Which heat pump is suitable for an apartment building?

Choosing the right heat pump for an apartment building depends on various factors, including the renovation stage of the building, the heating load, the type of heat distribution and the specific needs of the residents. air to water heat pumps are a cost-effective option to buy and can be flexibly installed in cascade form to effectively meet heating requirements. These pumps can also be fitted with soundproof housings to minimize noise pollution in densely populated urban areas.

Fresh water stations can be used in any living area to provide hot water. These independent units ensure that hot water is provided efficiently even at lower flow temperatures and help prevent legionella formation. Hot water heat pumps are particularly suitable for central water heating if a hot water tank is already available. The use of warm exhaust air, for example from a utility room, to generate hot water optimizes energy efficiency.

The combination of domestic water heat pumps with photovoltaic systems offers an innovative solution. By operating the heat pumps with environmentally friendly solar power from your own roof, you can reduce CO2 emissions and significantly reduce energy costs for tenants and apartment owners.

For well-insulated new buildings, air-to-air heat pumps an option while geothermal heat pumps with a SCOP value of 4 to 5 for large apartment buildings, are ideal to ensure an efficient and environmentally friendly heat supply. Geothermal heat pumps, which are characterized by high efficiency and consistent output, can supply heat even in extensive systems.

In older or poorly insulated buildings, where renovation to the usual low flow temperatures of 30 to 50 degrees Celsius is not sufficient, a high-temperature heat pump offers a suitable solution. It reaches flow temperatures of around 80 to 100 degrees Celsius and can also be used efficiently in buildings with large radiators.

The use of a buffer tank is essential to optimize heating output. This stores the generated heat from time to time and makes it available as needed. For an apartment building, these storage systems must be of correspondingly large dimensions in order to distribute heat efficiently and cover peak loads.

Finally, it is important to note that installing and selecting a heat pump in apartment buildings requires careful planning and expert implementation to ensure optimal performance and efficiency. Consultation with experts is therefore crucial to find the best and most cost-effective solution for each apartment building.

You can find out more about what types of heat pumps are there and how they work here.

What is the output of a heat pump for an apartment building?

The performance of a heat pump for an apartment building depends on various factors. This includes the heat load, cut-off times, heating limit temperature and required heating hours. These factors vary by building. In addition, depending on the standard outdoor temperature, i.e. the location.

The heat load is the heat demand that the building has, and the heating hours are the number of hours in which the heating must be switched on to meet the heat demand. You can find out more about this here.

In order to find a suitable heat pump for an apartment building, the exact heating load of the building must first be known. The heat load can be calculated by an energy consultant or a heating installer. As soon as the heat load is known, the required heat output of the heat pump can be determined.

Die Autarc software can help with this. With the autarc app, the heat load can be calculated quickly and easily using LiDAR Scan 2.0. More about this here.

The annual performance factor (JAZ) is a measure of the efficiency of a heat pump. It indicates how much heat a heat pump can generate per kilowatt hour of electricity. The higher the JAZ, the more efficient the heat pump is.

Efficient systems primarily help to save costs. Nevertheless, the corresponding system must first provide the performance required for an apartment building. If this is the case, the efficiency of the system can be considered.

The required output in kilowatts that a heat pump requires per square meter can be roughly determined using the following guidelines:

• Passive houses require around 0.015 kW per m2.
• In a new building with Efficiency House Standard 55, it is around 0.04 kW per m2.
• In a retroactively insulated old building, you can expect around 0.05 kW per m2.

It is important to choose the right size heat pump for the building. A heat pump that is too small may not provide enough heating capacity in winter, while a heat pump that is too large is unnecessarily expensive and can break down more quickly as it cycles more frequently.

New BEG funding limits for heat pumps in apartment buildings from 2024

Since the beginning of this year 2024, new regulations for BEG funding (federal funding for efficient buildings) have come into force, which apply specifically to residential buildings with several residential units. These changes affect owners and managers of apartment buildings who want to invest in energy-efficient heating systems such as heat pumps.

The new regulations set upper limits for the subsidized investment costs that apply to heating replacement in apartment buildings. For single-family homes or the first residential unit in an apartment building, the maximum funding is now 30,000

euro. For the second to sixth residential unit in an apartment building, the upper limit was set at 15,000 euros each. From the seventh residential unit, this limit is further reduced to 8,000 euros each time.

From End of May 2024 The following groups are eligible to apply for funding:

• Owners of existing apartment buildings that comprise more than one residential unit.
• Homeowners' associations (WEG) in Germany, provided that joint ownership measures are implemented.

The staggered funding rates increase with the size of residential complexes and are intended to facilitate heating upgrades in larger buildings. The adjustment of funding rates is a response to higher heating costs and the need to increase energy efficiency in German residential buildings.

The new funding rules will make it easier for homeowners to invest in modern heating technologies such as heat pumps. These save costs in the long term and also help with climate protection.

Owners of apartment buildings and WEGs should comply with the new funding guidelines. They offer financial support for the modernization of their heating systems.

It is recommended to talk to experts or authorities at an early stage. This makes it possible to clarify the exact requirements and opportunities for funding. In this way, the greatest possible benefit from financial incentives can be achieved.

conclusion

Heat pumps are an innovative solution that can operate efficiently and in an environmentally friendly manner, even in apartment buildings. The choice between centralized and decentralized systems should be based on building structure, occupant preferences and costs. Decentralized heat pumps enable individual control and reduce heat losses, while centralized systems can impress with economies of scale in purchase and maintenance.

The new BEG subsidies from 2024 significantly improve the accessibility and economic efficiency of heat pumps and promote the transition to sustainable heating methods. These subsidies facilitate investment and promote long-term savings and higher energy efficiency.

Overall, heat pumps not only offer an opportunity to reduce costs and become independent of fossil fuels, but also make a valuable contribution to climate protection. It is recommended to consult experts early on to ensure the best implementation. You should find the most suitable solution for your specific conditions and needs.

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