Flat-plate collectors (FPC) consist of a box with thermal insulation and a glass cover. The absorber is situated in this box. If the space between the absorber surface and the glass cover is evacuated, the collector is called a vacuum flat-plate collector. Flat-plate collectors are well suited for façade installation, where they provide an additional thermal insulation layer and a design element. During installation, however, care must be taken to avoid thermal bridges.
For special applications such as industrial process heat or solar air conditioning, flat-plate collectors do not yet achieve satisfactory efficiencies. Research is therefore being conducted to increase their efficiency specifically for operation at high temperatures.