Located in Lake Laka, Pszczyna, Poland, CO2-Saver Sustainable house was designed by P. Kuczia. The built form is designed to optimise the absorbance of solar energy. Approximately 80% of the building envelope facing south. The single storey living space on the ground floor is externally clad with untreated larch boarding. Solar energy is gained there by the set-in glazed patio. Solar collection panels are located on the roof and a photovoltaic system is planed for the future. The dark facade of the “black box” – a three storey structure clad with charcoal coloured fibre cement panels – is warmed by the sun, reducing heat loss to the environment. The passive and active solar energy concepts and a high standard of thermal insulation are enhanced by a ventilation plant with thermal recovery system.