Energy and heat transition:
pushing climate-friendly residential heating
Climate-friendly heat supply is the most important lever for reducing CO2 emissions in existing buildings
We will therefore be making greater use of the modern, future-oriented technology of highly efficient heat pumps in our properties in the coming years.
LEG uses different technologies depending on the neighbourhood and requirements. On the one hand, LEG relies on central air-to-water heat pumps, which are particularly suitable as a sustainable replacement for fossil fuel-powered central heating systems. On the other hand, decentralised air-to-air heat pumps are used, especially where gas floor heating systems have been used up to now.
In order to implement this transformation on a large scale, LEG Immobilien SE entered into a strategic partnership with Mitsubishi Electric in March 2023 on the subject of air-to-air heat pumps.
The aim is to replace existing decentralised gas heating systems primarily with innovative air-to-air heat pump technology. Following an initial phase, our goal is to gradually install these highly efficient heat pumps in LEG Immobilien SE's existing buildings.
To achieve this, LEG founded the joint venture dekarbo° in September 2023 together with Soeffing Kälte Klima GmbH.
As a solution provider, dekarbo° offers a package tailored to the housing industry consisting of heat pump installation, subsequent system support and operational management throughout the entire life cycle, as well as green electricity products, a tenant app and smart services. Based on a year of experience in the market and numerous air-to-air heat pumps already installed, we are convinced that decarbonisation for decentralised heated residential units means technological diversity. Our aim is to provide the best solution for every budget and every situation.
Our heat pump solutions are individually tailored to each building
At dekarbo°, we primarily equip buildings with decentralised heating systems with modern heat pumps: both air-to-air and air-to-water heat pumps. Our goal is to find the right solution for every building. Both technologies have their strengths, but not every system is suitable for every type of building.
Air-to-air heat pumps are particularly suitable for buildings with a high energy efficiency rating. This technology also comes into its own when there is little scope around the building to install larger monoblocks to supply several residential units. The major advantage of this technology is that it requires minimal intervention per flat from the tenant's point of view and offers the option of using a cooling function even in summer when temperatures are higher.
These types of heat pumps use the ambient air to provide heat directly in the living spaces and can significantly reduce CO₂ emissions. Installation can be carried out while the building is occupied and usually takes two to three days. Each unit is individually adjusted and connected to all living spaces via multi-split systems. In addition to installation, we also take care of integrating the hot water supply and, once completed, introduce tenants to the simple, efficient operation of the technology.
Air-to-water heat pumps, on the other hand, offer better energy efficiency ratings. They operate at lower flow temperatures but continue to use the existing radiators. For tenants, the heating behaviour remains familiar.
As the conversion is more complex for each building, we plan each project carefully. To do this, we carry out apartment inspections, create digital floor plans and coordinate all technical details so that the installation is as efficient and tenant-friendly as possible. In contrast to air-to-air heat pumps, we centralise the heating system and install new pipes up to the apartment transfer station.
We always decide whether to use air-to-air or air-to-water heat pumps based on the building structure, the technical requirements and the needs of the tenants. This ensures that every installation is not only technically sound, but also sustainable and future-proof.
dekarbo° attaches great importance to transparent communication and close support for tenants: from planning and installation to ongoing operation. The aim is to provide tenants with comprehensive information, keep disruption to their daily lives to a minimum and make the installation process as smooth as possible.
To this end, dekarbo° has developed its own process that can be easily implemented in occupied flats. This reduces noise and pollution and ensures comfort for tenants.
The Düsseldorf-based company Soeffing Kälte Klima GmbH is one of the regional market leaders in refrigeration and air-conditioning technology - founded more than 100 years ago and currently employing more than 100 people. Soeffing has always been strong in training and is well networked locally with guilds, chambers and regionally as well as supra-regionally (via Temtec Kälte-Klima GmbH). The company's technological orientation is particularly evident in its many years of experience in the use of natural refrigerants, especially for the food retail trade. The joint venture decarbo° offers a good solution for rapid decarbonisation and CO2 reduction with low costs and high efficiency.
Key data on the LEG Air-to-Heat campaign
- Potential (replacement of gas floor heating systems)
- 4 Mio. apartments nationwide
- 20,000 apartments of LEG
- CO2-savings
of 2,8 t per residential unit per year - High efficiency
of approx. 1:4 (1 kWh of energy generally generates 4 kWh of heating power) - Well proven technology
(e.g. in Scandinavia) in commercial, hotel and residential applications - Investment savings
LEG total by 2030: around 500 million euros - Neutral in terms of warm rents
with proper handling for residents with better living quality (cooling in summer; air-cleaning)
Press releases
07.03.2025 | So kann die Wärmepumpe die Gasheizung in der Wohnung ersetzen
26.07.2024 | Wärmepumpen-Offensive LEG: Dekarbonisierung der Bestände durch Einsatz von Klimageräten
23.07.2024 | Luft-Luft-Wärmepumpen-Offensive der LEG nimmt an Fahrt auf: Joint Venture dekarbo° startet durch und erhält zwei German Brand Awards|
10.03.2023 | Wärmepumpen-Offensive: LEG Immobilien und Mitsubishi Electric schließen strategische Partnerschaft
21.09.2023 | LEG und Soeffing gründen Gemeinschaftsunternehmen: Mit dekarbo° werden Gebäude schnell und effizient klimaneutral