Winter Curtains

What type of fabric would you suggest for winter curtains. We have really huge old windows with metal frames that let in a lot of cold air. I want to make heavy curtains, or put a layer of material on the backs of my current ones. Any suggestions? I am new at making my own things so I need something pretty simple.

Buy some of those cheap quilts from Walmart (make sure they are the same pattern) and fold over the tops. Then you have heavy quilted curtains that look nice for a few seasons.

This is actually cheaper than making the quilts your self but they really don't wash well for use on a bed.