Close-up on heat pumps

Our mission

As of January 1, 2024, every heating system must comply at least 65% of renewable energies. During the amendment of the Buildings Energy Act (GEG), the Federal Ministry for Economic Affairs and Climate Action developed a concept for the implementation of this 65% RES-rule, released for public discussion in the summer of 2022. As a contribution to this discussion, the German Federal Association for Heat Pumps commissioned Prognos AG to provide a numerical basis for the cost-effectiveness of heat pumps in rented apartment buildings in consideration of different parameters (price level, building type, etc.).

The project team examines the question of the social compatibility of such measures by examining the allocation of costs and their economic consequences for tenants and landlords. The uncertainties arising from the changed framework conditions for gas and electricity prices should also be made clear.

Our approach

The first step is to analyse and determine end customer prices for electricity and natural gas, taking into account the volatility and uncertainties of current price developments.

Since the building stock in Germany is very diverse, several technical building variants are being investigated (two building types, with and without optimisation of the secondary heating system).

Three heat generators are compared for each of the defined type buildings:

• An air-water heat pump
• A brine heat pump
• A natural gas boiler – as the most common system technology to date, for comparison

The necessary investment costs and assumptions regarding maintenance and operating costs are based on studies, our own estimates, and data provided by the customer. Due to the dynamic development of costs in recent years, the investment costs are calculated on the basis of appropriate indices (e.g. construction price index) for the year under review (2023), to be determined in the course of the project.

Current nationwide subsidies for heat pumps are taken into account.

Core results

As a result of the change in energy prices and the continuing availability of subsidies, the cost-effectiveness of heat pumps in moderately renovated apartment buildings has improved significantly compared to the use of fossil fuel heaters compared to previous years. Switching to a heat pump is now more economical than simply replacing a gas boiler with a new one. This can also help to offset sharply rising energy costs for renters.

Links and downloads

Result documentation (waermepumpe.de, PDF in German)

More information (waermepumpe.de, in German)

More about our work on this topic

Project team: Nils Thamling, Dominik Rau, Nora Langreder, Malek Sahnoun

Latest update: 11.10.2022