Ventilation is the supply of outdoor air to buildings. Ventilation is provided intentionally using fans and from airflow through open windows and doors. Ventilation, often called infiltration, also occurs when air leaks through cracks and holes in building envelopes. Ventilation helps reduce indoor concentrations of indoor-generated air pollutants; however, ventilation can also increase indoor concentrations of some types of pollutants from outdoor origin. Under many conditions, ventilation increases building energy use because admitted outdoor air must be heated, cooled and/or dehumidified.
The Indoor Environment Group has a long history of research on building ventilation. The Group studies how rates and methods of ventilation, including natural ventilation, affect indoor air pollutant concentrations as well as prevalence rates of acute "sick building" health symptoms, absence rates, work performance, and the risks of chronic adverse health effects. Methods of measuring ventilation rates and the use of sensors to automatically control rates of ventilation are developed and studied. The effects of ventilation on building energy use are evaluated. A key goal is to identify, or develop, the technologies and practices needed to maintain good indoor air quality without using more energy than necessary for ventilation. Much of the research yields information needed to formulate scientifically-supported minimum ventilation standards.