RobertsAllinsonLomasPorritt_AIVC_Paper_v1.6.pdf (655.81 kB)
Download file

The effect of refurbishment and trickle vents on airtightness: the case of a 1930s semi-detached house

Download (655.81 kB)
conference contribution
posted on 17.04.2018, 13:05 by Ben M RobertsBen M Roberts, David AllinsonDavid Allinson, Kevin LomasKevin Lomas, Stephen Porritt
As UK homes are insulated and draught proofed in an attempt to reduce wintertime heating demand they become more airtight. Any reduction in infiltration could have a detrimental effect on indoor air quality. Controllable background ventilation provided by trickle vents is one method of maintaining indoor air quality. A 1930s semi-detached 3-bedroom house was refurbished with double-glazed windows, trickle vents, doors and loft insulation. 167 blower door tests were carried out pre- and post-refurbishment between January and March 2017 to understand the repeatability of the test and quantify how trickle vents affect airtightness. The refurbishment reduced air leakage by 29% from 20.8 to 14.7m3/h/m2 at 50Pa (with all windows and trickle vents closed), but still in excess of the current UK regulations for new builds (10m3/h/m2 at 50Pa). Opening trickle vents provided limited additional ventilation, only increasing air change rate by 1.8m3/h/m2 with all vents open. The test was found to be repeatable with a standard error of 0.07m3/h/m2 at 50Pa with no relationship between the test result and wind speed or direction. The results lead to two important conclusions. Firstly, after refurbishing older homes of this type, infiltration rates are still well above recommendations for adequate indoor air quality. Secondly, the omission of trickle vents in older homes may not unduly diminish indoor air quality.


This research was made possible by Engineering and Physical Sciences Research Council (EPSRC) support for the London-Loughborough Centre for Doctoral Research in Energy Demand (grant EP/L01517X/1). Loughborough University is acknowledged for funding the majority of the refurbishments outlined in this paper and for continued maintenance of the test houses and security provision.



  • Architecture, Building and Civil Engineering

Published in

38th AIVC - 6th TightVent - 4th venticool Conference


369 - 380 (11)


ROBERTS, B.M. ... et al, 2017. The effect of refurbishment and trickle vents on airtightness: the case of a 1930s semi-detached house. Presented at the 38th AIVC - 6th TightVent - 4th venticool Conference, Nottingham, UK, 13-14 September 2017, pp.369-380.


AIVC (Air Infiltration and Ventilation Centre)


AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at:

Acceptance date


Publication date



This is a conference paper.




Nottingham, UK