There are three basic ways of heat transfer: heat conduction, convection and radiation. The heat transfer of the building is mostly the result of the combined effect of the three methods.

House Dress Jinbo ? reflection membrane gives off little heat and is used widely in heat insulation of roof and wall.

 Heat transmission route ( non reflective film ) : heat source -- infrared magnetic wave -- heat hits tiles to make the temperature rise -- tile becomes heat source to radiate heat energy -- heat hits the roof so that the temperature increases -- roof becomes heat source and gives off heat -- indoor temperature continues to rise

    Heat transmission route ( adding reflective film ) : heat source -- infrared magnetic wave -- heat hits tiles to make the temperature rise -- tile becomes heat source to radiate heat energy -- heat hits aluminum foil so that the temperature increases -- the radiation rate of  aluminum foil is very low -- indoor environment keeps comfortable temperature