Air infiltration and its effect in buildings. Rakennusten ilmavuotojen aiheuttajista ja vaikutuksista.

Points out that difficulty in calculating fortuitous ventilation in buildings caused by infiltration means that energy demand of a building contributed by it is scarcely ever known. Provides equations describing infiltration due to pressure differences, which in turn are caused by wind conditions, inside/ outdoor temperature differences and possible influence of mechanical ventilation systems. Describes computer program developed in Finland to calculate air infiltration. Demonstrates infiltration rates in houses. Stresses need to include infiltration in heating and air conditioning calculations.