Thermochromic coatings have great application potential in reducing the building’s heating and cooling load and improving the urban thermal environment. In order to investigate the factors influencing the optical properties of thermochromic coatings and optimize the material formulation

12 different thermochromic coatings with the color-changing temperature of 31°C were prepared by incorporating thermochromic powder with other assistant components. The effects of rutile TiO2 content on the spectral reflectance of the coatings were analyzed. The results show that the spectral reflectance of coatings increases with the content of TiO2. The optimum mass fraction for thermochromic powder is 5%

and for TiO2 is about 5%—10%

in which the solar reflectance of colorless phase is higher than that of colored phase by more than 0.2. At the same time

the effects of the particle size of TiO2 on the reflectivity of the coatings in different bands were investigated. The results show that the reflectivity of the thermochromic coatings decreases with the increase of TiO2 particle size in ultraviolet and visible light bands except red band. In the red and near-infrared bands

the reflectivity of the thermochromic coatings increases with the increase of TiO2 particle size.