Lining is a fabric sewn to the back of your drapery, sewn at the sides but not at the bottom. Depending on your preference, the advantages can range from enhanced sun protection, improved insulation, to increased light control.
Opting for lining can contribute to achieving the ideal finish, making the curtains softer, effectively blocking sunlight, reducing noise, and providing insulation against both heat and cold. This, in turn, helps minimize energy loss associated with windows.