IEC 60665:2018 specifies the performance and the corresponding methods of test of AC ventilating fans for household and similar purposes intended for air forcing and exhaust, driven by single-phase AC motors having a power consumption of less than 125 W (including any associated regulators) for use on single-phase AC circuits not exceeding 250 V. This document applies to ventilating fans such as partition fans for walls and windows and duct fans. This document does not apply to: - the safety of electric fans for household and similar purposes (IEC 60335-2- 80); - the performance of comfort fans (IEC 60879); - range hoods and other cooking fume extractors (IEC 61591); - airborne acoustic noise for fans (IEC 60704-2-7); - electromagnetic compatibility of fans (CISPR 14-1 and CISPR 14-2, IEC 61000-3-2, IEC 61000-3-3). This second edition cancels and replaces the first edition published in 1980. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) the test chambers have been updated; b) a test chamber for a type D fan is introduced.