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.
Ventilation losses account for approximately 50% of heat consumed by a building. Treats characteristics of leakage generally. Estimates that decrease of ventilation of building stock in Finland by 0.1 air changes per hour would save about 100 million f marks annually. Provides practical instructions for controlling building leakage rates.