This document specifies aerodynamic  acoustic and electrical power performance test methods for unidirectional ventilation units used in residential ventilation systems This document is applicable to ventilation units: - installed on a wall or in a window without any duct  A category  - installed in the upstream of a duct  B category  - installed in the downstream of a duct  C category  - installed in a duct  or with duct connection upstream and downstream  D category  - with one or several inlets/outlets  - installed in a system with a heat pump for domestic hot water or water for cooling or heating  - which can be used for supply or exhaust