This part of prEN xxxxx specifies the laboratory test methods and test requirements for testing of Aerodynamic, Thermal and Acoustic performances, and Electrical Power of a mechanical Supply and Exhaust ventilation unit used in a single dwelling. In general such a unit contains: - supply and exhaust air fans, - air filters, - air to air heat exchanger with/ without air to air heat pump for exhaust air heat recovery, - control system. Such equipement can be provided in more than one assembly, the separate assemblies of which are designed to be used together.