In this study, a feasibility for developing window films for energy efficiency in building based on poly(vinyl chloride) (PVC) composite was explored, using two different types of thermochromic pigments, such as vanadium dioxide (VO2) and thermoreversal-40. Using VO2, tensile properties of the PVC film improved, accompanied with an increase of percentage gelation of PVC. On the other hand, thermochromic behaviors, in the visible light region of the PVC/thermoreversal-40 film, were more obvious than those of the PVC/VO2 analog. The percentage of transmittance of the near infrared wave through the PVC/VO2 film was much lower than that transmitted through the PVC/thermoreversal-40 film. The above improvement was achieved at the expense of the thermal stability of the PVC film.