Improvement of air tightness of communities

From the beginning of year 2007 the buildings in Finland must have energy efficiency calculations, which requirements are now part of Building Codes, based on European Performance of Buildings Directive. According the renewed code, being into the force from July 2012, air tightness number q50 cannot be more than 4 m3/ (h*m2). Better air tightness can be shown by measurements. The air infiltration must be calculated in compensation calculations based on air tightness number 2.0 m3/ (h*m2). The energy efficiency requirements caused an immediate response in the building sector. Air tightness’s have been measured since 70`s but new requirements launched a real boom. For example, in the city of Oulu building supervision authorities connected air tightness in their quality control programs of buildings - before that the authorities demanded the moisture management and control plan for multi-story houses and commercial both public buildings.
More than 30 years ago, the typical air leakage number n50 in one-family houses varied in the level of 6 – 7 1/h (changes/hour). In the turn of millennium the level was 2-3 1/h, but for instance in the city of Oulu the air tightness of new one-family houses has elicited to improve to the level 1 1/h or even below that. The best result since now is 0, 1 1/h, in the target where special attention has paid in air tightness, measured by three measurers and four different Blower Doors.
In this presentation the progress of air tightness especially in one-family buildings has been considered, and how a city can effect on the quality of new buildings. The best case of 0, 1 1/h is introduced, also the structural details. Air tightness is just one part of energy efficiency control – when air leak number will be in the level of 0, 5 – 0, 6 1/h – in the level of passive house – the effect of air tightness is not so crucial dealing with energy consumption and energy savings. Also calculations of the influence of air tightness for energy consumption in various cases will be introduced.