Why WHR ventilation?
Modern houses are very well insulated with the purpose of saving energy. The better the insulation, the lower the energy consumption necessary for heating or cooling the house. A well-insulated house is financially attractive, but there is one downside: the house is hermetically sealed and that can lead to an unhealthy air quality. So good ventilation becomes indispensable for every house!
With mechanical ventilation or simply opening a window, the warm (or cool) air escapes the house and fresh outside air can just flow in, causing a loss of precious energy. Balanced ventilation with waste heat recovery prevents that.