UCL Institute for Environmental Design and Engineering


Field trials of pressure and humidity controlled ventilators

30 November 2016

Key facts

  • Funding Body/Client: The Department for Communities and the Local Government (DCLG) (e.g EPSRC, ETI)
  • Project Partners:  BSRIA
  • Total Project Value: N/A
  • UCL/IEDE Project Value Share: N/A
  • Duration: 2004-2007
  • Status:  Complete

The scope of this project led by BSRIA was to monitor the behaviour of ventilators and the effect they have on the internal environmental conditions under real life winter weather conditions. Three types of controlled ventilators were selected:

  • RH controlled (60% - 70% threshold)
  • Pressure controlled (<10 Pa threshold)
  • Pressure controlled (≈20 Pa threshold)

The ventilators were characterised in terms of energy consumption issues and potential effects on the quality of the indoor environment. The methodology involved installing each type of ventilator in turn in the same two bedroom house and releasing the moisture and sensible thermal load representative of occupants. Sensible heat loads and ultrasonic humidifiers were used to simulate the effects of occupancy in the house. The sensible heat loads represented the heat given off by a person and the humidifiers represented moisture released from breathing and 25% of water vapour produced by other household activities.

The other 75% was assumed to be removed by mechanical ventilation as this project was concerned with the ventilators and the background ventilation they provide. The reference case was passive ventilators installed in the test house. Alongside the field trials of the ventilators, a computer modelling exercise was being carried out aimed to model a year simulation of the passive ventilators and then apply the same simulation program to the three types of active ventilators. The modelling was seeded with the data measured in the field trials.


PI:  Ian Ridley

Co-Is: Tadj Oreszczyn and Michael Davies

R: Dejan Mumovic 


The following key publications were produced as a result of this project:

  • Ridley, I., Davies, M., Booth, W., Judd, C., Oreszczyn, T. and Mumovic, D. (2007) Automatic Ventilation Control of Trickle Ventilators, International Journal of Ventilation, Volume 5, Number 4, March 2007
  • Ridley, I., Davies, M., Oreszczyn, T., Mumovic, D. (2007) Hybrid controlled Trickle Ventilators, The 10th International Conference on Indoor Air Quality and Climate, Beijing , China.
  • Ridley, I., Davies, M., Booth, W., Judd, C., Oreszczyn, T. and Mumovic, D. (2008) Automatic Control of Trickle Ventilators, Department for Communities and Local Government, Building Regulations Division Project Number: CI 71/6/10 BD2423, London. 

The Final Report delivered for ODPM Building Regulations Division under the Building Operational Performance Framework. 


For further information please contact: Tadj Oreszczyn