Building integrated photovoltaic thermoelectric (BIPVTE) wall system is highly energy efficient and self adaptive to the environment. This sophisticated system is supported by the co-work of PV module for solar radiation transformation, air gap for thermal dissipation and thermoelectric radiant panel system (TERP) for active radiant cooling/heating. The purpose of this study is to develop an accurate and fast simulation method of this complex system which could be beneficial for system design, control and optimization for application. The present study upgraded the PV model by considering the variable resistance due to Peltier Effect in thermoelectric module. A new non-uniform time step model was proposed which can provide an improved and more efficient system simulation. The non-uniform time step solution of BIPVTE system was validated by comparing with both uniform time step solution and experimental data. The parametric studies on time step h and superposition number N under uniform time step solution, as well as two linear deviation coefficients d(T) and d(G) under non-uniform time step solution, were respectively analyzed. In uniform time step solution, the simulation time step h and parameter N should be properly chosen to balance simulation speed and accuracy. However, in non-uniform time step, numerical investigations demonstrated that simulation accuracy can be kept within an acceptable range even when linear deviation coefficients were large enough. The algorithm can be further accelerated by adopting Gauss-Berntsen-Espelid or Gauess-Kronrod rule in numerical integral calculation. The comparative and case study in this research has shown the validity and robustness of the proposed non-uniform time step model, which could be a useful tool for further work on BIPVTE as well as other building systems. (C) 2017 Elsevier Ltd. All rights reserved.