Originally Posted by BerdoR

hope this helps..
"Maximum light absorption and heat insulation in a curtain is created through a lined curtain, which typically consists of an uncoated fabric at the front to provide the look and feel of the curtain, with a separate coated fabric attached at the rear to provide the insulative qualities. The coated fabric is typically referred to as a lining, which simply refers to a coated fabric that does not have any particular colour or pattern"