Despite　transportation,　buildings　contribute　to　the　largest　CO2　emissions.　The　building　retrofit　work　has　a　big　potential　on　energy　saving.　However,　recent　years　in　China　most　of　building　retrofit　works　focus　on　the　high-rise　building　in　city　center,　the　faraway　suburban　areas　building　still　in　a　poor　situation　which　not　only　bring　huge　CO2　emissions　every　year　but　also　affect　people＇s　life　comfort　when　cold　winter　coming.　In　this　research　analyzed　how　to　do　the　retrofit　design　for　suburban　area　bungalows　by　DesignBuilder　modelling　while　consider　the　cost.　The　research　proved　the　design　is　effectiveness　for　the　bungalow＇s　insulation　performance.　Meanwhile,　confirmed　the　retrofitted　house＇s　performance　standard　when　comparing　with　domestic　standard　and　two　main　stream　standards　of　the　world.　©　Conference　Proceedings　of　the　10th　International　Symposium　on　Project　Management,　China,　ISPM　2022.