As a series of our research on energy conservation and thermal comfort of detached houses havingcentralized HVAC systems, sensitivity analysis on feasibility of space cooling with outdoor air wasconducted using Design of Experiment(DOE). Effects of varied parameters on building thermal loadwere examined for five cities such as Tokyo and Osaka that have different weather conditions within themilder climate area of Japan. Building performance(insulation and airtightness performance, solarshading), air conditioning system(setting temperature level, outdoor airflow rate) were selected as theparameters which effect on annual heating load(AHL), annual cooling load(ACL), cooling load duringintermediate season(ICL).The results of the analysis of variance are 1) three parameters (insulation and airtightness performance,solar shading, setting temperature level) except for outdoor airflow rate are significant in AHL in all fivecities. 2) all four parameters are significant in ACL in all five cities. 3) solar shading and outdoor airflowrate are significant parameters in ICL in common with all five cities, but some locations show a differenttendency in significant parameters which is caused by the difference of climate conditions duringintermediate season. 4) solar shading level has an effect on ICL by the interaction with outdoor airflowrate.