This document provides procedures and methods for measuring and calculating the energy efficiency and associated characteristics of non-residential unidirectional ventilation units when driven by electric motors. Unidirectional ventilation units include roof fans and box fans. This document includes unidirectional ventilation units with and without filters. Additional air treatment items are considered in this document but are excluded in the determination of the efficiency of the product. This document does not include: ?? residential unidirectional and bidirectional ventilation units@ ?? non-residential bidirectional ventilation units. NOTE 1 Residential unidirectional ventilation units are under the remit of CEN/TC 156/WG 2. NOTE 2 Non-residential bidirectional ventilation units are under the remit of CEN/TC 156/WG 5.