It is really cold here this morning minus something….. I am so glad that all my roman blinds have interlinings in them, it just gives that extra layer of warmth.  I closed the curtain in front of the door last night, it is in front of a double glazed door but what a difference it makes.  Never mind solar panels generating electricity save the heat escaping in the first place!  If you are having curtains or blinds made to order unless the fabric is extremely thick interlining is an extra layer which does work as noise and heat block and makes curtains hang better too.