As someone familiar only with heavy, rubber-backed insulated drapes, I think the manufacturers seriously under-promoted that aspect of this product in the description. I can't believe how soft they are, and how well they hang and drape, nothing like the old insulated curtains. The fabric has a rich feel, but silky smooth, and it completely blocks the light, even direct sunlight. You may have a little light bleed through at the top where the rod is, but the fabric itself is totally, surprisingly, opaque. You can't tell if it's day or night, at least through the fabric. All of us online shoppers know the feeling of buying an item, and, once it arrives, finding out that it somehow doesn't live up to our expectations. This product exceeded my expectations, and will probably go into my Hall of Fame of Great Online Finds. Score one for the shopper!