Heating,　ventilation,　and　air　conditioning　(HVAC)　systems,　combined　with　the　internal　thermal　mass　of　buildings,　have　been　deemed　to　be　promising　means　of　providing　demand　response　(DR)　resources,　particularly　for　buildings　with　active　energy　storage　systems.　DR　resources,　such　as　peak-load　reduction　potential,　can　provide　grid-responsive　support　resulting　in　a　high　degree　of　grid　involvement　and　high　flexible　electricity　demand.　In　the　DR　field,　the　potential　of　HVAC　load　flexibility　has　been　considered　in　buildings.　In　the　future　smart　buildings,　it　is　important　to　take　advantage　of　demand-side　resources　to　achieve　real-time　energy　supply-demand　balance　sustainably.　In　this　context,　DR　potential　and　characteristics　of　buildings　play　a　pivotal　role　in　DR　programs.　However,　few　studies　have　investigated　the　internal　thermal　mass＇s　heat　release　and　DR　characteristics　of　buildings.　Thus,　a　systematic　experiment　is　conducted　to　study　the　DR　potential　and　characteristics　of　internal　thermal　mass　and　active　storage　systems.　The　DR　resources　include　the　passive　cooling　storage　from　furniture,　building　envelope　and　an　active　water　storage　tank.　Two　DR　control　strategies,　including　pre-cooling　and　temperature　resetting,　are　analyzed　in　this　study.　The　experimental　results　show　that　the　strategies　are　effective　for　short-term　(0.5　h)　and　intermediate-term　(2　h)　DR　programs.　For　a　long-term　DR　program,　active　energy　storage　technology　such　as　a　water　storage　tank　is　required　to　satisfy　the　occupant＇s　comfort　requirements.　Hence,　we　conclude　that　passive　thermal　mass　and　active　storage　systems　should　be　simultaneously　considered　in　practical　DR　programs　for　better　DR　implementation.