A Comparative Study of the Indoor Environmental Quality in Renovated and Non-Renovated Classrooms

Christian Anker Hviid, Henrik N. Knudsen, Jakob Markvart

Research output: Contribution to book/anthology/report/conference proceedingArticle in proceedingResearchpeer-review


This paper reports on a comparative study of the indoor environment in two adjacent classrooms, one renovated, and the other non-renovated. The aim of the study was to investigate the positive consequences of renovating lassrooms, but also to disclose unanticipated side-effects. The non-renovated classroom was without mechanical ventilation, fitted with woodwool ceiling plates for acoustics and lighting fixtures with horizontal illuminances of 200-300 lux on the tables. The renovated classroom was retrofitted with a new acoustic ceiling made from perforated gypsum tiles and suspended lighting fixtures and mechanical ventilation via decentral room unit mounted below the ceiling. The ventilation air was supplied in the void above the acoustic ceiling, which distributes air through perforations and joints in the ceiling to the occupied zone – a concept often referred to as diffuse ventilation. In this setup, the acoustic ceiling also acted as silencer for the ventilation inlet. Different indoor environmental parameters were comparatively measured in each classroom,
including longterm CO2-concentration, temperature and noise levels as well as reverberation time and technical noise from the ventilation equipment. In all respects, the objective measurements improved in the renovated classroom.
Interviews with pupils and questionnaire surveys were conducted, and – while showing less evidence of the improvements than expected – did indicate increased user satisfaction with the retrofit.
Original languageEnglish
Title of host publicationRoomvent&Ventilation 2018 proceedings : Excellent Indoor Climate and High Performing Ventilation
EditorsRisto Kosonen, Mervi Ahola, Jarkko Narvanne
PublisherSIY Indoor Air Information Oy
Publication dateJun 2018
ISBN (Electronic)978-952-5236-48-4
Publication statusPublished - Jun 2018
EventRoomvent 2018: International Conference on Air Distribution in Rooms - Aalto University, ,Finland, Espoo, Finland
Duration: 2 Jun 20185 Jun 2018


ConferenceRoomvent 2018
LocationAalto University, ,Finland
Internet address


  • ventilation, schools, indoor environmental quality, air distribution

Fingerprint Dive into the research topics of 'A Comparative Study of the Indoor Environmental Quality in Renovated and Non-Renovated Classrooms'. Together they form a unique fingerprint.

Cite this