heroal roller shutters save heating energy and serve as passive air conditioners. In cold nights, the loss of energy is considerably reduced by the air cushion between window and roller shutter. With closed roller shutters, up to 44 % of energy can be saved at night. In the summer, automatically controlled roller shutters keep the inside temperature cool and enjoyable, and make switching on the air conditioning unnecessary. In addition, completely surface-mounted shutter boxes do not create any cavities and hence no thermal bridges, considerably improving the heat insulation of the building. Tightly sealing end strips ensure the heat-insulating and energy cost-saving function of heroal roller shutters.