January 17, 2025, 4:28 pm | Read time: 6 minutes
More interested parties, different questions: There are more and different aspects that must be considered when deciding to install a heat pump in an apartment building than when deciding to do so in a single-family home. Experts explain them.
Rising energy prices, growing environmental awareness: The heat pump is increasingly coming into focus as an alternative heating solution. It is already standard in new buildings. It is also an option for older buildings – including apartment buildings with shared ownership. There is no one-size-fits-all solution, as each building needs its own heating plan depending on a number of factors. However, owners’ associations need to ask themselves specific questions along the way. Below, HOMEBOOK provides answers to the most important ones.
Overview
- 1. What Are the Advantages of Installing a Heat Pump in an Apartment Building?
- 2. What Level of Refurbishment Does a House with a Heat Pump Need?
- 3. How Much Space Does the Heat Pump Need?
- 4. Which Type of Heat Pump is Recommended for Apartment Buildings?
- 5. Better a Centralized or Decentralized System?
- 6. Do All Radiators Have to Be Replaced?
- 7. Where Can I Get Expert Advice?
- 8. What Is the Legal Situation in a Condominium Association?
- 9. What Subsidies Are Available?
1. What Are the Advantages of Installing a Heat Pump in an Apartment Building?
A heat pump and its installation cost a lot. However, the pump protects the environment and your wallet in the long term, as its energy efficiency is better. “The heat pump works one for four,” explains Tomas Titz, first chairman of the GIH – the association representing the interests of energy consultants in Lower Saxony: “One kilowatt of electricity generates four kilowatts of heat at best.” In addition to reducing CO2 emissions and independence from fossil fuels, heat pumps can, therefore, lead to lower operating costs in the long term. They also often increase the value of the property.
2. What Level of Refurbishment Does a House with a Heat Pump Need?
As a general rule, the energy status of the building is crucial, especially the insulation. Heat pumps work most efficiently when the house has a low heat requirement due to good insulation. For properties that are already well insulated, the installation of a heat pump alone can mean energy optimization.
However, the measure is often part of a renovation roadmap that is defined for the building in question, ideally with the help of an energy consultant. “If the top story ceiling, basement ceiling, exterior walls, and windows are the larger construction site, this is preferable,” says Tomas Titz. This is because the heat pump should be geared towards future heating requirements.
3. How Much Space Does the Heat Pump Need?
There’s no general answer to this question because apart from the type of pump, the dimensions depend on the heat load and the condition of the building. “The better insulated the building envelope is, the smaller the technology needs to be and the cheaper it will be,” says Titz. A lean and efficient solution, therefore, requires that no heat is lost due to a lack of insulation.
According to Matthias Wagnitz, energy and heating technology consultant at the German Central Association for Sanitary, Heating and Air Conditioning, the components in the building should “not be much larger than the existing boiler” in very well-insulated buildings. In this case, it may be possible to manage without a buffer tank, the intermediate buffer for the blocking period, because the building does not cool down. For the outdoor components, it depends on which type of energy generation you choose, whether from the ground, the air, or the groundwater. The space requirements vary considerably in some cases.
4. Which Type of Heat Pump is Recommended for Apartment Buildings?
This depends on the space available and the heat sources. Brine-to-water heat pumps (geothermal heat pumps) require a borehole or trench for laying the geothermal probes. Water-to-water heat pumps use groundwater, for which a suction well and an absorption well must be built near the house. Both projects require approval and are more expensive than other heat pumps. However, they work very efficiently. Air-to-water heat pumps, which draw their energy from the ambient air, are somewhat easier and cheaper to install.
However, the fans of these appliances produce audible noises. Although somewhat quieter than the earlier models, “it makes a difference whether you want to get ten or 100 kilowatts out of the fan,” says Matthias Wagnitz. It is advisable to choose a location that is within sufficient distance of living rooms and bedrooms, neighboring buildings, and passers-by.
5. Better a Centralized or Decentralized System?
The decision often depends on the existing supply and the space available. Decentralized solutions have the advantage that they can be individually aligned, controlled, and billed more precisely. However, multiple devices also mean higher costs. “With an air-to-water heat pump, for example, each apartment has an outdoor unit,” explains Katja Weinhold from the German Heat Pump Association (BWP).
“Some air-to-air heat pumps are also able to heat well in terms of efficiency,” says Wagnitz. Here, too, every home is equipped with such a device. Mixed systems can also be an option, “such as central heat generation with transfer stations at the apartments,” says Weinhold.
6. Do All Radiators Have to Be Replaced?
Not necessarily. “The decisive factor is whether the radiators can heat the room at a low flow temperature,” says Katja Weinhold. The best way to check this is on a cold day in winter by turning down the flow temperature of the current heating system to 55 degrees (after hydraulic balancing) and turning up all the radiators. “You’ll quickly notice whether what’s coming out is enough,” she says. In most cases, more radiators can remain than expected, as planning used to be more generous. Individual radiators that cannot cope with lowering the flow temperature can be replaced with larger models. If you have little space, you can use a low-temperature radiator.
7. Where Can I Get Expert Advice?
Thomas Zwingmann, head of the Energy and Climate group at the NRW consumer advice center, recommends three points of contact: Firstly, energy consultants with experience in energy planning can help with the preparations, such as calculating the heating load. It can also be worth consulting a certified energy consultant with regard to subsidies. On the other hand, manufacturers with experience in the use of heat pumps in apartment buildings can be contacted. In addition, some planning and engineering offices specialize in this technology. The German Heat Pump Association also offers a search for specialist companies on the website waermepumpe.de/fachpartnersuche.
8. What Is the Legal Situation in a Condominium Association?
As a rule, the decision to install a heat pump must be taken at an owners’ meeting. A majority resolution is required. In addition, legal requirements such as the Home Ownership Act and local building regulations must be observed.

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9. What Subsidies Are Available?
In order to be eligible for federal subsidies, WEG or the building must meet certain requirements. They must also commission a certified energy consultant. This appointment is subsidized. The experts on the Energy Efficiency Expert List (EEE) draw up an individual renovation roadmap for the planning and implementation of energy efficiency measures in the COA. Important: The application must be submitted via the online portal of the responsible Federal Office of Economics and Export Control (BAFA) before the project is initiated.
With material from dpa