Author: Bärbel Epp
Many new largely solar-heated houses in Germany are multi-family buildings, and their number is growing, according to Sonnenhaus-Institut (Solar House Institute), an alliance of about 300 architects, planners, building companies and system integrators that specialise in the design or construction of houses where sunlight provides at least 50 % of the heat and, in some cases, electricity a year.
The photo shows two multi-family buildings that were put up in Cottbus in 2018 and that meet over 60 % of their residents’ heating needs via a 100 m2 solar system and a 24,600-litre seasonal storage tank.
After the funding opportunities for solar thermal were extended this January, there has been a notable jump in applications for solar-heated one- and two-family homes.
In the first half of 2020, BAFA, the agency managing the German Market Rebate Programme, received as many as 105 applications for solar houses, whereas only 24 were submitted during all of last year.
The steep increase was the result of favourable funding options, such as grants that meet 30 % of the cost of large solar fields and storage.
The subsidy covers up to 80 % of the additional cost for the energy supply systems in primarily solar-heated houses, according to calculations by the group.
In its latest annual report, published at the end of 2019, the alliance’s co-chair, Georg Dasch, described a number of key market trends.
For example, single-family homes made up the bulk of largely solar-heated houses for years, before the concept has been now shifted towards multi-family houses and industrial facilities.
In addition, he noted that a number of solar houses can now also be found in the northern regions of Germany, at latitudes that come with lower irradiation levels.
The country’s northernmost solar home has been put up in Kiel on the Baltic Sea coast (see the map above).
Photovoltaic technology is gaining traction in the solar housing market as well.
A new solar house design that uses PV generators to power heat pumps has been a favourite among owners of single-family buildings in recent years, explained Rainer Körner, who co-chairs Sonnenhaus-Institut with Dasch.
In 2014, the alliance decided to broaden the definition of what constitutes a largely solar-heated house.
From that year on, a solar house no longer had to have a large solar thermal system and a storage tank to meet over 50 % of a building’s yearly heat demand.
A PV generator that powers more than 50 % of the electricity demand of the heat pump over the year also meets the alliance’s criteria.
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