Ventilation controlled by requirements. Behovstyrt ventilation.

Indicates that 35-70% of a building's annual energy consumption is used by ventilation plant. Notes difficulty in determining which energy saving measures are most profitable but states that restricting fresh air supply tothat required is one measure that has not been considered and that most systems are designed for maximum capacity without facilities for varying load according to conditions. Describes plant which uses CO2-controlled ventilation in a sports hall. Illustrates circadian changes.