Buildings of KIER that were constructed in 1980 consume much energy, because of outworn equipments(boiler, refrigerator, fan coil unit, piping) and windows facing to the west of main research building and irrational operation of H.V.A.C system. The purpose of this study is to present retrofit measures for the improvement of energy performance and indoor environment on KIER building by investigation and testing actual living conditions. From these results, we obtained 27.6% energy saving of heating and cooling load in KIER building. (author). refs., figs., tabs.