Savings through geothermal heat pump technology in combination with self-generated photovoltaic electricity

Lieboch in Steiermark, Austria

An easy to use and cost saving heating solution

“The result was even better than we expected. For our 260 m² house with pool, our energy costs are only 600 to 800 euros per year. The system runs smoothly via EEBus and is very easy to control via the app.”

General house and system information

The facts

The energy concept


The facts

The facts

  • New building using solid construction methods
  • Detached family house
  • 260 m² living space
  • 25 cm masonry and 25 cm hemp insulation
  • Heated swimming pool in the garden

The energy concept

The energy concept

  • Ground-source heat pump flexoTHERM exclusive VWF 87/4 (9 kW) installed with two boreholes that are 100 m deep for heating and passive cooling
  • Hot water cylinder uniSTOR exclusive VIH RW 500/3 MR (500 litre), which has been awarded the Green iQ label for especially sustainable and efficient products
  • Solar heating system auroTHERM plus VFK for hot water and to heat the pool
  • Controlled ventilation of the living space with recoVAIR VAR 360
  • Photovoltaic system auroPOWER VPV P 305 (8.5 kWp) – SMA inverter and Sunny Home Manager 2.0
  • Battery storage system eloPACK VSE (24 kW)
  • Digital control of heating via multiMATIC VRC 700 system controller including multiMATIC app
  • Manufacturer-independent networking via EEBus platform



This ground-source heat pump system is installed in the Steiermark region of Austria, Lieboch.

An investment in the future

A modern and intelligently networked house is an investment in the future because it enables long term savings on energy costs. The Rappold family’s new home was equipped with state-of-the-art technology – both in terms of heating appliances and energy efficiency. After only one year of construction, the family’s sustainable “smart home” was ready for them to move in and was equipped with a building services system second to none – including digital heating control.

The starting point

When building their new home, the Rappold family was keen to use future-oriented and networked home appliances. Electricity and heat from renewable energy sources need to be used at maximum efficiency in order to minimise operating costs and emissions. So it was particularly important to make the best possible use of the free electricity generated by the photovoltaic system – either for the heat pump or for household electricity.

The solution

To achieve maximum energy efficiency, the appliances in a networked system need to “talk” to each other. Via EEBUS, a manufacturer- and technology-independent language for communication between devices, the components of the system work cooperatively. This means that the heat pump and the photovoltaic system form a unit when they communicate with each other and react accordingly. For example, the temperature in the hot water cylinder is increased by the heat pump from 45 °C to 65 °C using free photovoltaic electricity, or the cylinder is heated outside of the time window if it is not yet full. In this way, the free, self-generated electricity is used optimally and even more heat can be stored, which can be used later when the sun is not shining. This leads to more efficiency, which reduces energy costs.

With the free multiMATIC app, the Rappold family can easily choose from different energy management strategies for heating and hot water.

The recoVAIR controlled living space ventilation system ensures fresh and healthy air throughout the house despite the well-sealed construction.

In addition, the heat pump is supplemented by the auroTHERM solar heating system to heat hot water and to heat the pool in summer. Together with the self-generated electricity from the photovoltaic system, the Rappolds are totally self-sufficient in energy in their house from March to October.

Why Vaillant?

The Rappold family were satisfied with Vaillant appliances in their previous house. They knew from their installer that Vaillant was ahead in terms of networked building appliances and digital heating control. Vaillant’s direct expert advice was also very helpful during the planning phase.

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