There are many different systems to make windows energy saving. Draperies or sliding fabric panels keep drafts out and heat in. But if you dislike lots of fabric at the window or want a more comtemporary approach, there are other options.
A built-in look is tidier and more modern - vertical blinds, shutters framed by the outer edges of the window, or even window shades or venetian blinds confined within an architectural frame.
A less conventional system is the shojii. These sliding panels of rice paper, now also made of Plexiglas or thin plastic, can be tremendous energy savers. Orginally designed for Japanese houses as both inner and outer partitions, these sliding walls are at once versatile and decorative.
In contemporary homes, of course, thin paper walls cannot be used as outer doors, but they cab be used in many ways indoors. In one house I designed, for example, the architect had opened one wall of the master nedroom to a two-story garden room on the floor below. This was a beautiful idea, but it didn't work. Not only was it impossible to control the flow of light from the garden room's huge windows into the bedroom; it was also impossible to keep the bedroom warm on winter days. So, a sliding shojii wall of delicate wood-paper was installed on the low partition separating one room from another.
And in the living room of a new home, a picture window looked out on a busy street. This broda expanse of glass-with-no-view also faced north, making a very cold room. I designed and inner wall, built of 2-by-4s and dry-wall, with a generous circular "window" cut out of the middle. Behind this, I designed a pair of shojii doors to slide on a ceiling an floor track invisible from the inside, neat and tidy from the street. The doors could be opened to look out or allow more light in. When closed, they protected the seating area fromcold air and the undesirable view.