Factors affecting the performance of ventilation systems in large buildings.

Reviews the results of IRC research on some key factors that influence the performance of a ventilation system in large buildings. It discusses the effects of these factors and provides guidelines for operating the system efficiently. Improving the airtightness of older buildings will reduce air leakage and cold drafts, and help reduce energy use by improving the performance of ventilation systems. To reduce energy use, it is necessary to reduce contamination sources as much as possible either by using environmentally friendly furnishings, materials and products, or by exhausting contaminants at the source if possible. General ventilation should then be used. For buildings where the number of occupants varies significantly with time, such as office complexes and schools, it may be possible to further improve energy efficiency by controlling their ventilation rates based on the actual number of occupants at a given time.