The Passive House Institute in Darmstadt issues certificates for building materials and technical systems such as heat pumps and ventilation systems in order to enable cross-product comparability between the various manufacturers. For this purpose, the heat recovery rates of ventilation systems are also determined according to uniform criteria. Due to leaks on the wall of the device or inadequate insulation of the device, air and heat can penetrate from the installation room and influence the result of heat transfer. The same effect is achieved by leaks in the ducts within the heat exchanger, which allow warm exhaust air to mix with the outside air. This is taken into account by the Passive House Institute in the certificates with a malus, which results in sometimes lower heat supply rates than in the specifications of the respective manufacturers. Devices that do not have the certificate of the Passive House Institute are also given a malus in the energy balance according to the Passive House Project Planning Package (PHPP).
Source: bauwion
