Building leakage, infiltration and energy performance analyses for Finnish detached houses

This study focuses on the correlation between the airtightness of a building envelope and the average infiltration and energy consumption of a typical modern Finnish detached house. The correlation between tightness and infiltration was determined using an empirically validated dynamic IDA-ICE simulation model of a two-storey detached house. The effect of wind conditions, Finnish climate conditions, balance of ventilation system and leakage distribution on infiltration were studied with the simulation model. According to the results, the average infiltration rate and heat energy consumption increase almost linearly with the building leakage rate n50 of the building envelope. Resulting from the linear dependence, the annual average infiltration rate of the detached house in a sheltered suburban area can be approximated with the simple equation n50/31. If the average infiltration rate is applied to heat energy calculations, the simple equation is n50/25.