This part of EN 13141 specifies the laboratory test methods and test requirements for the testing of aerodynamic, thermal and acoustic performance, and the electrical performance characteristic of a mechanical supply and exhaust ventilation unit used in a single dwelling. It covers unit that contain at least, within one or more casing: supply and exhaust air fans; air filters; air-to-air heat exchanger and/or Extract Air-to-Outdoor Air heat pump for extract air heat recovery; control system. Such unit can be provided in more than one assembly, the separate assemblies of which are designed to be used together. The different possible arrangements of heat recovery heat exchangers and/or heat pumps are described in Annex A. This standard does not deal with non-ducted units or reciprocating heat exchangers. This standard does not deal with units, which supply several dwelling. This standard does not cover ventilation systems that may also provide water space heating and hot water. This standard does not cover units including combustion engine driven compression heat pumps and absorption heat pump. Electrical safety requirements are given in EN 60335-2-40 and EN 60335-2-80.