Window treatments, those things one does to or around windows to improve appearance and reduce the amount of sunlight permitted to enter a room, are like many other aspects of constructing a green home. Some are very green and others are not.
Key factors to look for when shopping for green window treatments are their insulating value (r value), higher numbers being better, and their shading coefficient, a direct measure of the heat traveling through the window treatment, with lower numbers being better. Ideally, the window treatment will have a high r value, a low shading coefficient, be made from renewable resources, and have a very minimal effect on the air quality where they are used.
All window treatments provide some insulation value. However, certain materials and designs such as, Honeycomb shades, vertical blinds, and real wood blinds insulate better than others, like aluminum blinds or roller shades. Thick, lined drapes are also a good choice for providing good insulation with window treatments. The less heat and light they allow in, the better insulation they are providing.
Using renewable materials such as bamboo or natural fabrics, cotton, silk, and hemp, is far better than using synthetics that are made mostly from petroleum distillates. Bamboo has a shape that makes it not very efficient when used as blinds, but it does work well as curtain rods. Limiting the distance that materials must travel to reach you is also important. Items that must come from halfway around the world lose any green benefits with the energy requirements of transportation.
Air quality is another major concern when shopping for window treatments. Many synthetic materials emit toxic materials into the air as they age and oxidize. Dioxin, a known carcinogen, has been linked to the use of plastic window shades. Polyester and nylon window treatments are often treated with flame retardant chemicals which can leach into the air and have serious health related repercussions for those sensitive to such things.
The odds are that it will be impossible to find any one window treatment that is 100% green. However, a little bit of research into the various options available can make it possible for a homeowner to make an informed decision based on what his needs are and what his budget can handle. Certain compromises may be required in order to obtain the most environmentally friendly products made from renewable materials that will provide a high insulation value at the windows and will have a minimum impact on the local air quality.
The key to adding green window treatments is to make a determination of how much insulation is required, can it be achieved using window treatments made from renewable materials, and can I avoid the use of chemical compounds in the window treatments I choose so that I do not have to worry about the quality of the air my family breaths.
Looking at each factor, strike a balance based on what you can and cannot tolerate in each area and make a purchase of a product that meets or exceeds your minimum requirements in all three areas.