Energy-efficient refurbishment - heating optimization in existing buildings using the example of Würzburg

The project not only demonstrates smart solutions in new builds, but also that existing buildings can - and must - be retrofitted with climate-efficient equipment. We present the measures.

In cooperation with a service provider for heating monitoring, ROCKETHOME has shown Stadtbau Würzburg how energy cost savings in existing buildings can be achieved through subsequent optimization. In this article, we explain how heating system monitoring and management have helped to make Würzburg's properties fit for the future.

With its large housing stock, the German housing market is the largest in the European Union. It is therefore not surprising that, in addition to climate-efficient new buildings, the focus is and must be on optimizing existing buildings. The aim is to make the building stock climate-neutral by 2045.

"Around 85% of our portfolio was built between 1950 and 1958 and between 1964 and 1974. Keeping this portfolio fit for the future and permanently rentable has always been a core task. The climate protection requirements reinforce the already existing need to focus on the development of our housing stock in the coming years and decades." - Hans Sartoris, former Managing Director of Stadtbau Würzburg
Stefan Stangenberg, Konstantin Wismath

Working together for digital solutions in buildings

With a housing stock of over 5,000 apartments, Stadtbau Würzburg GmbH is the largest landlord in Würzburg. By cooperating with us, ROCKETHOME, and our partner for heating optimization, the housing association shows that its focus is not only on future-oriented new buildings, but also on the energy-efficient refurbishment of existing buildings. As part of the joint initiative, the heating systems in buildings in two districts of Würzburg were equipped with digital measurement technology. A pilot project on smart heating was also launched.

Optimization of the new building

The foundation stone for the Hubland construction project was laid on June 3, 2016. On the former US barracks site, known as the Hubland area in the north of Würzburg, apartments of various designs and sizes have been created for different residents. The property has now been connected to the ROCKETHOME property management platform and the building has been equipped with intelligent heating system optimizations in terms of consumption and error transparency as well as monitoring.

Optimization of existing properties

The buildings on Frankfurter Strasse in the Zellerau district of Würzburg are older and therefore do not have an adequate environmental footprint. To improve this, the property management platform and digital measurement technology were also implemented here. This allows errors and irregularities in energy consumption to be identified and optimized more quickly.

Existing building on Frankfurter Strasse

Efficient solutions for the building

Efficient building management solutions offer a holistic approach to the digitalization and future-oriented design of properties. Smart monitoring and optimization of heating systems creates transparency in the building. In Würzburg, the partner solutions from othermo were integrated for this purpose, enabling measured values, signals and meter and operating data to be recorded. This data is used to generate detailed reports on energy consumption, CO2 savings and the efficiency of the heating systems. Our property management platform (Property Manager) serves as a central management tool and enables seamless control of the othermo interface.

In the event of a fault, a notification is sent immediately by email or text message with a description of the fault to make it easier for employees to rectify the problem. The property management platform's administration interface also offers functions such as service forms, a marketplace and document exchange. Features that are not only helpful for Stadtbau Würzburg and its tenants, but also facilitate communication between both parties. This holistic solution considerably simplifies the maintenance and management of heating systems and ultimately leads to more efficient building management.

  • Smart monitoring and optimization of heating systems: transparency in the building - partner integration othermo
  • Use of the ROCKETHOME management platform (Property Manager) and app as a management product
  • Other possible uses: The Property Manager offers solutions for the management of buildings, users, communication tools and much more


  • Energy cost savings: Heating costs can be reduced through central monitoring and secure remote control of heating systems
  • CO2 reduction: More efficient heating control reduces energy consumption and therefore also CO2 emissions
  • Proactive maintenance: The system recognizes potential maintenance requirements at an early stage and helps to avoid expensive breakdowns and repairs
  • Cross-manufacturer and cross-technology solution

Smart heating - pilot project for apartments

Smart thermostats were installed to test the function of smart heating in the residential units. This means that residents can not only control and configure their heating via an app, but also save energy and money.


  • Saving energy in the apartments: Individual control of the thermostats enables residents to set the heating precisely as required
  • Ease of use: residents can conveniently control their heating via the app and set individual preferences
  • Automation: Event-controlled automation increases convenience and energy efficiency
  • Multisensor: Indoor climate monitoring: Multisensors can monitor temperature and humidity to ensure a comfortable indoor climate

You can find more information about the ROCKETHOME IoT module Smart Heating here.

(from left to right) Maximilian Weigand (Technical Property Management Stadtbau Würzburg), Stefan Stangenberg (Project Manager ROCKETHOME), Luis Meuer (Project and Development Engineer othermo) in front of the new Hubland building
District heating main station


The collaboration demonstrates how innovative technologies and digital solutions can make existing buildings fit for the future. The implementation of smart heating system optimizations and heating monitoring not only contribute to energy efficiency and CO2 reduction, but also improve transparency and efficiency in building management.

Project participants

In addition to the in-kind services in the form of integrated modules, ROCKETHOME also acts as a service provider. From content-related introductions to the provision of a project manager for the duration of the pilot project: the service character plays an important role at ROCKETHOME. This not only guarantees adherence to time, budget and a smooth process, but also creates trust.

  • Overall project management: Stadtbau Würzburg
  • Project implementation: tradespeople and electricians from Stadtbau Würzburg
  • ROCKETHOME Project management: Stefan Stangenberg, ROCKETHOME, Cologne
  • Service provider for heating monitoring: othermo, Bavaria

Stadtbau Würzburg

Stadtbau Würzburg. With more than 11,000 residents, almost 10% of Würzburg's population live in an apartment owned by Stadtbau Würzburg GmbH. The vision of the housing association is the constant modernization of the housing stock in order to provide housing for people of all income levels in addition to new construction projects. For Stadtbau Würzburg, social responsibility means not only providing properties, but also having an ecological vision.


With othermos digitalization and optimization of heating systems and energy centers, the utility service provider enables efficient and energy-saving living. othermos solution consists of an IoT gateway, which is installed in the boiler room, and our web portal to reduce energy consumption and CO2 emissions.

Are you also interested in digitizing your building? Then please write to us here.

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