Solar energy through a window is transferred or transmitted by infrared waves. Radiant energy is converted to heat when it strikes people or objects. If you block the transfer of this energy you keep it from turning into heat because it never strikes an object. Efficient Energy Saving Window Film interrupts the transfer of this energy by reflecting the energy back.
Transmission is basically the percentage of Solar energy (UV + Visible Light + Near Infrared) that can passes through a window. Reflection is the ratio of solar energy reflected back to the source, expressed as a percentage. Absorption is the percentage of solar energy absorbed to that of the total solar energy.
With solar window film installed on the inside of a window, the proportions are changed dramatically, with reflected energy and absorption increasing. This corresponds to a reduction in solar heat transmitted inside the room or the automobile. The properties of the window film dramatically influence how and in what way transmission, reflection and absorption change.