Needs determine type of window coverings

The word window is derived from an old Norse word for wind, “vindr,” combined with “auga” meaning eye, resulting in the word vindauga. Literally translated, window means the eye of the house through which wind enters. Now aren’t you glad you learned that? Be sure to bring it up at your next golf outing so you can impress your friends!

Here is some more exciting data. Glass used for many windows consists of about 70 percent silica sand, 13 percent lime, 12 percent soda, plus small amounts of other materials such as metal. Heated to a melting point, this combination is transformed into a viscose liquid that, when cooled, becomes hard. Glass is inherently liquid, which explains why cracks spread. Plain glass has no internal bonds to stop a crack or prevent it from shattering. Tempered glass, however, is much stronger than plain glass. It will not crack, shatter or break easily.

The primary function of windows is illumination. Natural light has been proven to be healthful as it contains all the types of rays in a balanced, full spectrum. The only type of ray that is harmful is the ultraviolet light, which may be blocked out with low-emission glass or solar screens. Plenty of natural light filtering into a room can be uplifting, and that is why we enjoy being in a room with many or big windows. A general rule of thumb is that window square footage should equal at least 10 percent of floor space.

The color and texture of the walls and interior furnishings are affected and have an effect on the natural light shining though the windows. Soft colors and smooth textures will cause natural light to appear brighter and clearer while dark colors and rough textures will deepen and soften light. It is helpful to know this when you are trying to establish atmosphere in a room.

There are times when you want to block out most or all light. Window coverings that accomplish this include draperies with blackout linings, solidly interlaced woven woods, opaque vinyl roller shades, blackout-lined or insulated fabric shades, opaque vertical louvers and fully closed horizontal blinds. Over some of these treatments it might also be necessary to add a lambrequin (an upholstered board that surrounds the window) or a valance and side fabric treatments. The original treatment will block light from coming through the window while the lambrequin or valance and side fabric treatment will catch the peripheral light peaking out the sides and top.

Window coverings that screen light include knit and woven casement draperies, lace, sheer fabrics, and light-weight and thin fabrics. Horizontal and vertical blinds, when partially open, will filter light; pleated, translucent shades have the same effect.

Treatments that do not obstruct light include sheer fabrics, fully opened horizontal and vertical blinds and any treatment that, when open, stack off the glass completely.

Besides glass type — double, triple pane, insulated, etc. — the energy conservation via windows is commensurate with the window coverings. The coverings that completely block light will be the most energy efficient, while the window treatments that do not obstruct light at all will be the least efficient.

Rosemary Sadez Friedmann, an interior designer in Naples, Fla., is author of “Mystery of Color.”