The engineering of the surPLUShome begins with the idea for the interior design as a single room. This increases the capacity of thermal mass in the space as well as it reduces the necessities for natural and mechanical ventilation or the energy demands for lighting. We adjusted the area of windows and their energy transmission of solar radiation in an early stage of planning. Other parameter was the thermal mass which we increased by latent storage in plasterboards. And we installed a natural ventilation system which allows cross ventilation for high reliability of operation.
To reduce the Transmission heat losses, all opaque walls have a u-value of 0.077 W/m²K in the standard assembly which is about 3 times better than the actual requirements in Germany. The 5 cm thin vacuum insulation panel (VIP) equals a standard insulation of 40 cm. to reduce heat bridges, the VIP layer is mounted continuously all over the building envelope. The building features as well a high insulation in glazing. The triple glazing has a u-value under 0.8 W/m²K.
To reduce the heat losses by air, the building shell is constructed airtight and we analyzed the performance of the shell during construction with a Blower-Door-Test. Overall, these passive measurements of the surPLUShome result in a heat energy demand of 14.9 kW/m²a. Therefore it is a Passive House.