That is because Approximately 75% heat in the air is transmitted through radiation. Most materials used on buildings absorb the radiant heat and then re-radiate it. This results in higher room temperature than outside temperature in summer and lower in winter.
Woven Fabric Laminated Reflective Aluminium Foil, with a thermal radiation blocking rate of 97%, uses most of the energy incident on the surface to be reflected back to the source.
The absorption of thermal radiation will generate heat. The high emissivity and refractive index of the aluminum film determine that it has excellent thermal insulation properties.