Glass building windows can conduct sunlight into the building but on the other hand, and due to high thermal conductivity, they have a negative impact on the energy consumption in the building. Since the transparent PCMs usually have a low thermal conductivity, they can be used as an insulator for this matter.
These materials have low thermal conductivity and a high light transmission (in the liquid phase) so they can store the heat. Many PCMs have high transparency for visible light; however, they absorb infrared radiation, and it gives them the ability to be used in buildings’ glasses.