When it comes to saving on your energy bill, curtains designed for insulation are the top pick. While all curtains offer some insulation, those made with energy efficiency in mind are the best choice. Insulated curtains typically consist of layers of heavy fabrics like velvet or denim. These layers include high-density foam to prevent air transfer, a reflective film layer, and a vapor barrier coating that retains indoor air and minimizes heat transfer into your home.