The aim of this Chapter is to break down barriers to concepts of natural ventilation. The study is part of a Pan European project titled NatVent that involves seven countries in the north of Europe. The project leaders are the UK Building Research establishment. Urban pollution is a major barrier to the adoption of natural ventilation, so successful ways of avoiding these problems need to be found.

Ventilation is essential for the maintenance of good indoor air quality, although there is evidence to suggest that energy loss through uncontrolled or unnecessary air infiltration is excessive. In this study; estimates are presented for air change (ventilation and infiltration) energy use in non-industrial buildings for 13 countries. Various methods are used for the estimates, but they are mainly based on calculating the total annual enthalpy change needed for the conditioning of air. The potential for reduced energy use by improved ventilation control is also briefly reviewed.

In a recent survey of quantity surveyors, most believed that energy-efficient buildings are more expensive to build than conventional ones. But it isn't necessarily so by any means.

The main purpose of buildings is to provide a comfortable living environment for their occupants. This includes, among others, thermal,visual and acoustic comfort as well as indoor air quality. Except during the 1950's and 1960's, it has always been considered important that an excess use of energy should be avoided in the construction and the management of a building, sometimes even at the cost of user comfort. Energy saving is, however, not the main purpose of the building.