In this study, a hybrid ventilation system was proposed to reduce indoor heating and cooling loads owing to ventilation by using the heat storage and discharge effects of some heat storage materials. A pilot system of the ventilating system, comprised of heat storage material, a filter, as well as supply and exhaust fans, was also built. To measure the energy saving performance of the system, the following quantitative indicators were used: heat storage time, heat discharge time, heat storage material efficiency and reduction of ventilation loads. These indicators were measured based on actual data gathered from four test operations. The result shows that polycarbonate-based heat storage material has a longer heat discharge time compared to heat storage time, and a reduced ventilation heating load by over 37%. (c) 2012 Elsevier B.V. All rights reserved.