One year of realignment at Sonnenhaus Institut

03.02.2016
In order to qualify as a Sonnenhaus, a building must cover at least 50% of its heating requirements using solar energy. Solar thermal energy is usually used for this purpose. (Photo: Schlagmann Poroton/ Sonnenhaus Institut)
In order to qualify as a Sonnenhaus, a building must cover at least 50% of its heating requirements using solar energy. Solar thermal energy is usually used for this purpose. (Photo: Schlagmann Poroton / Sonnenhaus Institut)

2015 was the first full calendar year following the realignment of the Sonnenhaus Institut, which allowed the combination of photovoltaics and heat pump for the first time. Most Sonnenhaus homes are still heated using solar thermal systems, but photovoltaics are also finding their place.

According to the Sonnenhaus Institut, a total of 154 Sonnenhaus homes were built in 2015. Solar thermal is still the most commonly used source of heat, but nine of the houses (about 6%) are now equipped with a large photovoltaic system for own consumption and some of them also have a heat pump. However, the houses do not rely exclusively on photovoltaic modules.

Solar technologies work together

KHB Creativ-Wohnbau in Heilbronn, for example, built a Sonnenhaus home with an air-water heat pump and a 9.4 kW photovoltaic system (approximately 62 m²), but it is also equipped with 15 m² of solar collectors. The solar electricity is not only used for the heat pump, but also for household applications. The PV system covers approximately 42% of the building's requirements.

Solar thermal and photovoltaics cover 60% of the heating demand of the building, which has a floor space of 284 m².

Heat pumps are often criticised because they mainly use fossil energy in the winter when levels of solar radiation are low as well as on windless days. The Heilbronn Sonnenhaus also addresses this problem: a wood-fired tiled stove can be used for heating.

Multi-family Sonnenhaus homes are becoming more important

In addition, the Sonnenhaus Institut reports that the trend towards multi-family homes is continuing to strengthen. Even though 66% of the Sonnenhaus homes built in 2015 were single-family homes, at least 17% had two or three residential units, and 15% had even more than three residential units. The remaining 2% are commercial buildings.

According to a recent press release from Sonnenhaus, the larger the building is, the more economical it is. This is also one of the reasons why this area in particular is gaining importance.

In total, there are 1,800 Sonnenhaus homes in Germany, Austria, Switzerland and Italy

Jan Gesthuizen