VA Passive House can only function with a highly efficient heat recovery, as ventilation systems without heat recovery waste far more energy per year than a Passive House uses for heat (at the same rate of air exchange, a ventilation unit without heat recovery may lose about 24kWh/(m²yr) whereas a Passive House’s maximum space heating demand is only 15kWh/(m²yr).
The ventilation systems used in Passive Houses must thus have heat recovery efficiencies of at least 75% while the electricity consumption for such systems should not exceed 0.45 Wh/m³ of the transport air volume. Additionally, the acoustic load of the ventilation systems for use in Passive Houses should not exceed 25dB. Pipes and values should be planned accordingly, making use of silencers.