Dusseldorf. The heating season will soon begin in Germany. Given the currently high costs for oil and gas, many households are expecting additional payments on heating costs this year - rightly so. The consulting company co2online estimates that in 2026 the costs for oil heating will rise by 24 percent compared to the previous year. An increase of 17 percent is expected for wood pellet heating systems. The basis for the estimates is a 70 square meter apartment in an apartment building.
According to figures from the non-profit consulting company co2online, heat pumps perform significantly better. The consultants only expect their heating costs to increase by three percent. It is therefore hardly surprising that heat pumps were the best-selling heating system in Germany in the first half of 2026 with 194,500 systems. Gas heaters come in second place with 134,000 units.
In the first half of this year, sales of heat pumps benefited from the generous funding provided by the Building Energy Act. However, the regulations of the Building Modernization Act already apply to new funding applications from the state development bank KfW. This law has been in effect since July 29th.
For most households, the subsidies for replacing the heating system are lower than under the old law. It remains to be seen how noticeable the reduced funding will be when installing heat pumps.
Germany has a lot of catching up to do when it comes to replacing heating systems. The Federal Association of the German Heating Industry (BDH) puts the number of heaters that are more than 30 years old at around four million. Overall, 40 percent of the 21.5 million heating systems are not state-of-the-art.
The energy service provider Techem still sees a lot of potential for the installation of heat pumps in existing properties, especially in multi-family homes. To date, heat pumps have primarily been installed in single-family homes. One reason for this is that in apartment buildings in densely built-up cities it is more difficult to comply with the required distances and noise regulations for the operation of heat pumps.
In addition, many apartment buildings are owned by homeowners' associations. Before replacing the heating system, the apartment owners must come to an agreement among themselves. However, these communities are often divided, especially when it comes to expensive construction projects. Instead of replacing the heating system, many homeowners' associations simply repair it.
However, Techem's current study did not address these legal hurdles. It's more about whether installing heat pumps is technically possible and economically sensible.
According to the study, 40 percent of apartment buildings in Germany could be equipped with heat pumps even without replacing radiators. If the property owners also replace the old radiators with modern low-temperature radiators, the rate increases to 90 percent.
Replacing radiators makes sense because heat pumps work with lower flow temperatures than, for example, central heating systems that run on gas. Low-temperature radiators can deliver heat to living spaces over a larger surface area. The water in the radiators therefore needs a lower temperature to generate the same room heat.
Whether simply replacing the radiators is enough for a heat pump to work economically depends on the individual property. However, it is usually much cheaper to replace radiators than to install underfloor heating or insulate the building's outer shell. An energy consultant can assess which measures make sense in individual cases after an on-site appointment.
Compared to other European countries, the potential for heat pumps in apartment buildings in Germany is high. According to the Techem study, the potential in Switzerland without replacing radiators is just 14 percent. If low-temperature radiators were installed, the rate would increase to 68 percent.
However, the potential in European countries cannot be compared one to one. In Switzerland, a quarter of buildings are already equipped with a heat pump, but in Germany the proportion is still less than ten percent. This means that the Swiss have already made significant progress in replacing heating systems. This also explains the greater potential in Germany.
This text was first published by WirtschaftsWoche.
