Excellent energy balance

The building services for this new-build apartment building are designed in such a way that more solar power is generated than is required for the heat pump. Room temperatures are even more comfortable thanks to comfort ventilation and “free cooling” during the summer.

Making way for the future

An old chalet had to make room for a new, Minergie P-standard apartment building—in favour of energy efficiency, sustainability, high-density construction.

Modern in the old quarter

Amongst mostly family homes, a modern, Minergie P-standard apartment building was built in 2016. Thanks to optimal use of the slope, the building integrates itself into the neighbourhood without appearing to dominate.

Meticulous planning

The building owner placed particular emphasis on using high-quality materials and harmonising the building services such that the energy balance was excellent.

Renewable energy supply

Photovoltaic systems, solar collectors, and CTA heat pumps using the latest technology ensure that heating is efficient and energy consumption is kept to a minimum. The energy balance is excellent: Therefore, the energy gain from the collectors is greater than the electricity consumption of the heat pumps for the entire building. With comfort ventilation, pleasant room temperatures are guaranteed. In addition, on hot summer days, the geothermal probes are used to naturally cool the attic apartment—without using the heat pump. This is done using the free cooling function.

The boiler room with the Optiheat Inverta Economy geothermal heat pump and free cooling function.

Heating in winter, cooling in summer

The two Optiheat heat pumps provide hot water for the shower, pleasant room temperatures during the winter, and, thanks to “free cooling”, a bit more cooling on hot summer days. Its own photovoltaic system supplies the power for the heat pumps.

Two heat pumps in use

Two brine/water heat pumps ensure that the entire building is heated and domestic hot water is prepared: The “Optiheat Inverta Economy” heats a 1,000-litre domestic hot water tank, a 500-litre buffer storage tank and four out of five residential units. The “Optiheat Inverta TWW” heats the fifth residential unit. The domestic hot water tank is already incorporated into this appliance and holds 220 litres.


In brief

  • New-build, Minergie-standard apartment building

  • An Optiheat Inverta Economy geothermal heat pump with free cooling, that heats a 1,000-litre domestic hot water tank and a 500-litre buffer storage tank, and also heats four out of five residential units.

  • An Optiheat Inverta TWW geothermal heat pump heats one of the residential units and also provides hot water using an integrated boiler.

  • A wine cellar split air conditioning unit provides the ideal storage temperature for fine wines.

  • The apartment building’s roof-mounted photovoltaic system


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