Although solar thermal systems are technologically mature and cost effective, they have not yet been sufficiently used in building design to play an adequate role in the reduction of fossil fuel consumption. One main hindrance to adoption is the generally low architectural design quality of the building integration of these thermal systems.

As confirmed by the example of photovoltaics, improvement of the architectural quality of building integrated systems can increase the use of a solar technology even more than price reductions or technical advances. Solar thermal collectors have...