Demand Controlled Ventilation will become necessary in order to meet the stated requirements for energy demand in future building regulations. The purpose of this report is to contribute with understanding and knowledge of Demand Controlled Ventilation in general, focussing on the optimization and development of pressure controlled systems in particular. Inadequate positioning of pressure sensors, skewed air distribution between duct outlets, unnecessary damper pressure drops and thereby reduced energy efficiency related to fan power, are typical problems for these systems. These are issues which this report sets out to highlight and preferably find solutions to and thereby improve this type of regulatory principle. The report include literary studies, laboratory measurements, calculations using a purpose designed mathematical tool and interviews with professionals. The report documents that in most cases it will reasonable to place the static pressure sensor towards the end of the main duct. This will provide the best distribution of air in most cases. Results also confirm that a positioning late in the duct system will give the most stable static pressure measurements. Calculations show that duct network with equal dimension throughout the whole main duct have the most stable pressure changes, which increases the stability and robustness of the ventilation system. Combined with lower pressure drop in the main duct, this gives a higher authority over the variable airflow dampers and improves the SFP-factor. With the help of workshops with experts, it was established a number of demands that will contribute to more energy efficient and robust ventilation systems in practice.