Ventilation
After removing pollutant sources as far as practicable, adequate ventilation is the next most significant element to consider in maintaining internal air quality. Recommended ventilation rates for rooms vary, depending on room function, the type and age of building, number of occupants, etc. Too much ventilation results in poor comfort for building occupants, and increased energy consumption. To reduce energy consumption, heat exchangers can be used to preheat incoming air. Air can also be recirculated to reduce heat loss.
Typically, natural ventilation solutions consume less energy than sealed buildings. However, natural ventilation cannot always be pursued if, for example, the building is adjacent to a source of air (or noise) pollution.