Five semi-structured interviews were conducted between December 2019 and January 2020 as part of a project investigating ventilation in UK homes. The main focus was related to the participants' ventilation practices: the things they did in their homes which were likely to affect ventilation or likely to affect indoor air quality and therefore the amount of ventilation needed. The homes were built with continuous mechanical extract ventilation (MEV) systems, and the interviews also aimed elicit information about the interpretation and use of the planned ventilation system. Full details of the research and case studies and interview data collection are available in the following PhD thesis:Few, J. (2021) Ventilation in occupied homes: measurement, performance and sociotechnical perspectives. University College London. https://discovery.ucl.ac.uk/id/eprint/10130632/