This　study　provides　a　reference　for　estimating　the　building　envelope　thermal　performance　at　the　initial　stage　of　design　for　nearly　zero-energy　buildings　in　different　climate　zones.　A　simplified　model　of　heat　load　prediction,　which　combines　the　quasi-steady-state　thermal　balance　calculation　procedure　in　ISO　52016　and　the　variable-base　degree-days　method,　was　proposed.　Therefore,　a　building　energy　performance　evaluation　tool　BPT　V1.0　was　developed.　Subsequently,　the　simplified　model　was　validated　through　comparative　analysis　with　the　Building　Energy　Simulation　Test　(BESTEST)　standard　procedure.　To　conduct　a　feasibility　analysis　of　the　development　tool,　case　studies　were　performed　on　the　performance　evaluation　of　building　envelopes　of　residential　and　office　buildings　in　different　climate　zones　in　China.　Compared　to　the　simulation　results　from　EnergyPlus,　the　deviation　of　heat　load　calculated　by　BPT　V1.0　was　within　10%,　which　further　verifies　the　applicability　of　the　tool　under　different　climatic　conditions.　Annual　heat　load　under　different　thermal　performance　building　envelopes　was　calculated　through　BPT　V1.0.　The　building　energy　efficiency　improvement　rates　were　found　to　range　from　30　to　60%　in　nearly　zero-energy　buildings　in　different　climate　zones　in　China.　The　study　results　can　provide　a　reference　for　energy　managers　and　a　basis　for　estimating　the　building　energy　efficiency　performance　with　different　envelope　thermal　properties　in　the　region.　©　2023　by　the　authors.