Entirely solar-heated blocks of flats in Switzerland
 Entirely solar-heated blocks of flats in Switzerland

Entirely solar-heated blocks of flats in Switzerland

Switzerland’s solar thermal market showed a slight increase last year, thanks to growing demand for solar hot water systems in multi-family houses. According to a press release from Switzerland’s solar industry association Swissolar on 11 July, glazed and unglazed collector area increased to 69,331 m2, a rise of 4 % compared to a year earlier. The area used to heat water in multi-family buildings jumped as much as 35 %. Every year, the association conducts a survey among suppliers of the technology on behalf of the Swiss Federal Office of Energy.
Photo: Jenni Energietechnik

Swissolar emphasised that the solar thermal market seemed to have stabilised after experiencing a sharp decline for 4 years. For example, it showed a significant 43 % year-over-year decrease in 2016. The authors of the survey predict a stable outlook for solar heating and cooling this year, though they state that cantons must stop delaying the implementation of the revised energy efficiency standards which are part of the MuKEn building regulations. They limit non-renewable heat production to 90 % for retrofits and to 80 % for newbuilds and need to come into force in every canton by 2020, which is thought to increase demand for solar space heating in the building industry.

One well-known technology supplier of solar solutions for the housing industry in Switzerland is Jenni Energietechnik, a manufacturer of storage tanks. The company announced that it had transported as well as installed a 110 m3 steel tank in a multi-family building in Huttwil (see the photo above). The 12-tonne unit was manufactured in Jenni’s factory in the Emmental valley and will supply heat to the building’s eight flats. 

The tank will be installed vertically in the centre of the low-energy building. The water-filled tank will be used for storing thermal energy from a 160 m2 solar field, so that the hot water and, via an underfloor system, space heating needs of the families can be met all year round. The first multi-family house entirely heated by solar energy will be ready for move-in by spring 2019. Another two buildings based on the same design will follow.


No. of housing units

8 flats (four times 4.5 rooms and four times 5.5 rooms) for let or purchase

Living space

Around 1,100 m2

No. of storeys

4 storeys

Solar fraction of space heating and hot water

100 %

Emergency heating system

Pellet boiler (one for all three multi-family buildings)

Solar field

160 m2 on south part of roof

Seasonal storage tank capacity

110 m3

Key figures of first-ever solar-heated multi-family house in Huttwil, Switzerland
Source: Jenni Energietechnik

In 2016, Jenni Energietechnik celebrated 40 years since the company was established. Its tanks come in many sizes and are designed for not only seasonal or daily storage but also heat recovery. In 1982, management set up Jenni Liegenschaften, which constructed three fully solar-heated multi-family houses in Oberburg, Switzerland, between 2007 and 2015.

Organisations mentioned in this article:


Baerbel Epp

Bärbel Epp is Founder and Director of the German communication and market research agency solrico and editor-in-chief of solarthermalworld.org