Concern over the energy consumption and environmental impact of ventilation and air conditioning systems is growing, as is concern over indoor pollutant levels and their impact on occupant health and wellbeing. This paper discusses the incorporation of photocatalytic reactor systems into a building’s ventilation/indoor air quality control strategy and assesses this strategy as a means to reduce energy consumption whilst maintaining indoor air quality. An approach for modelling photocatalytic reactor systems has been verified using experimental data, and incorporated into an indoor air quality model based on single compartment mass balance equations.