CdTe PV cell is one perfect candidate for window application because of its good daylighting performance, low-temperature coefficient and excellent electrical performance under weak light. In addition, thermal catalytic oxidation is an thermal driven air purification technology and the thermal energy can be easily obtained from PV window systems. Therefore, a novel thermal-catalytic CdTe double-layer breathing window was proposed. Firstly, the electrical, thermal and daylighting performances of proposed window were investigated experimentally. Secondly, the removal of formaldehyde was investigated using the verified coupled formaldehyde mass transfer and thermal-catalytic reaction kinetic model. Finally, the evolution of indoor formaldehyde concentration considering formaldehyde release source was calculated. Main results were: (1) The thermal and electrical efficiencies were respectively 0.297 and 0.0715, which were closed to the reported results. Also, the proposed window had better daylighting uniformity compared with conventional window. (2) The total generated clean air was 25.7 m(3)/(m(2).day), with the equivalent formaldehyde degradation efficiency of 0.010 based on purification performances of various air purifiers in market. (3) The comprehensive thermal efficiency was 0.518, with increase of 9.28% considering the contribution from formaldehyde removal. (4) The proposed window could make the indoor concentration approach to standard concentration under most working conditions. (c) 2020 Published by Elsevier Ltd.