Homeowners unite to demonstrate efficacy of heat pump systems
In the picturesque town of Bad Schwartau, Germany, an apartment building on Muhlenburg has undergone a remarkable transformation. Once reliant on gas and district heating, the building has transitioned to a renewable heating solution, demonstrating the effectiveness and cost-efficiency of such systems in practice.
Effectiveness
Energy Efficiency
The heart of this transformation lies in the installation of three aroTHERM plus heat pumps, two allSTOR plus storage systems, a condensing boiler as a backup, and two aguaFLOW exclusiv ground-source heat pumps. These systems are highly efficient, transferring existing ambient or ground heat rather than generating heat by burning fuels.
As a result, the building's energy consumption has been significantly reduced compared to conventional fossil fuel boilers. The new heating system boasts a seasonal performance factor (SPF) of 4.0, meaning it produces 4 units of heat for every unit of electrical energy consumed.
Renewable Heat Generation
These heat pumps use electricity (which can be renewable) to extract heat from air or ground, substantially lowering greenhouse gas emissions if the electricity comes from renewable sources. In the Bad Schwartau project, integrating these heat pumps contributed notably to the building’s renewable heat quota, aligning with Germany’s energy transition goals.
Compatibility with Existing Buildings
Despite the building's age and the challenges posed by larger heating demands and less insulation, the systems were paired with appropriate building envelope improvements and adaptations to the existing heating distribution systems, optimizing performance. The aroTHERM plus is designed for easy retrofitting, ensuring minimal disruption and compatibility with existing heating infrastructure.
Cost-Efficiency
Initial Investment and Payback
The initial cost of installing heat pumps and associated equipment in older buildings is higher than simply replacing old boilers with new fossil-fuel ones. However, the Bad Schwartau project showed upfront costs being offset by reduced fuel consumption over time. Typical payback periods in such retrofits can range from 5 to 10 years, depending on energy prices, subsidies, and building characteristics.
Operational Costs
Heat pumps generally have lower operational costs than oil or gas boilers due to their high efficiency and use of electricity, especially when paired with self-generated renewable electricity (like PV). In the Bad Schwartau retrofit, operational cost savings were observed due to the efficient systems and local availability of renewable energy.
Maintenance and Lifespan
Heat pumps generally require less maintenance than combustion-based systems, reducing ongoing costs and improving cost-efficiency over the system’s 15–20 year lifespan or longer.
Subsidies and Incentives
Government incentives, especially in Germany, help offset capital costs for renewable heat technologies, improving cost-effectiveness. The Bad Schwartau case benefited from such programs, making the heat pump retrofit financially feasible.
Summary
The aroTHERM plus and aguaFLOW exclusiv heat pumps have proven effective at delivering renewable, efficient heating in retrofitted older buildings, reducing energy use and carbon emissions significantly. While the upfront costs are higher, operational savings, lower maintenance, and subsidies make these systems cost-efficient over time.
This project in Bad Schwartau serves as a practical demonstration that heat pump retrofits—when well-planned and executed with building improvements—are both technically effective and financially viable renewable heating solutions for older building stock. The building, once heating the entire neighborhood with oil and later gas, now heats itself using sun, air, and common sense.
- The effectiveness of the transformation in the Bad Schwartau apartment building, as demonstrated by the installation of heat pumps, storage systems, and a condensing boiler, lies in their high energy efficiency, which transfers existing heat rather than generating heat by burning fuels.
- The heat pumps in the Bad Schwartau project, which use renewable electricity to extract heat from air or ground, significantly lower greenhouse gas emissions and contribute to the building's renewable heat quota, supporting Germany's energy transition goals.
- Despite the challenges posed by the building's age, the heat pump retrofit in Bad Schwartau is cost-efficient in the long run due to operational savings, lower maintenance, extended lifespan, and subsidies, making renewable heating solutions a viable option for older building stock.
