Measured and building code values of air change rates in residential buildings.

Since 1970 measurements of air change rate have been carried out in about one thousand buildings by the Swedish Institute for Building Research (SIB). In this paper we present results from these measurements. The studied buildings are of various design and have ventilation systems of different types, natural as well as mechanical. The buildings include single family houses, row houses, and multi family residential buildings, erected between 1900 and 1982. The measurements have then been carried out using tracer gas (decay) techniques to determine the rate of air exchange. Other collected data include building geometry, building design, and meteorological conditions at the time of the measurement. The outdoor conditions have varied. In the analysis the buildings have been divided into groups according to the year of construction, building design, and type of ventilation system. The measured rate of air change is compared to that required by the Code for each group of buildings. In many cases measurements have been carried out before and after retrofits aiming at saving energy. For a lot of buildings pressurization measurements as well as tracer gas measurements have been done simultaneously. In these cases we have also estimated the airtightness of different building categories.