Indoor air quality (IAQ) in the use of combustion appliances is important for adequate evaluation of air pollution health risks. Since people spend most of their time inside buildings, especially the elderly and children, their exposure to indoor air contaminants can increase health problems in the community. Combustion materials emitted from combustion space heating appliances in housing during the winter may become a serious problem to health, since sources of ventilation are usually left closed to obtain a comfortable temperature level. To evaluate the IAQ and factors that may decrease combustion materials emitted from heaters, a study was done by using a house exposure model. The study found that IAQ in an unventilated house during combustion heater use was poor due to lack of fresh air. When using a heater, natural ventilation should be used to dilute air contaminants emitted from the heater. A concentration of carbon dioxide at about 1000 ppm and a comfortable temperature of 20°C could be maintained by applying natural ventilation of about 0.12 m^2 during the use of an unvented kerosene space heater. However, ventilation also depends on the number of the occupants and the wind velocity. The use of a steamer is also important to provide optimum humidity levels without elevating the respirable dust concentration above the acceptable limit.