Ventilation calculation is important for prediction of heating/cooling load and indoor air quality in residential buildings. In past several decades, many simulation programs are developed for building research and design, but they generally need many input data and complicated modeling. A simplified and accurate prediction method is essential for speedy and convenient ventilation calculation during building design and performance evaluation. In this paper, thousands of ventilation cases are calculated by COMIS ventilation simulation program for a single room house. Using simulated results and ventilation theory, a simplified model and chart for ventilation rate is proposed in consideration of building air-tightness, type of ventilation system and climatic condition. By comparison of COMIS program and the simplified method, it can be found that there is a good agreement with relative error of less than 5 %. In addition, this simplified method is used for a study on building air-tightness level of a solar house having a forced supply ventilation system of heated outdoor air by solar collectors.
