The products you use to cover your windows will not only affect the aesthetics of the room, they will also affect the room's air quality as well as the heating and cooling costs of your room.

Curtains

Drapery fabrics can be made of either natural fibers like cotton, linen, silk, and wool, or petroleum-based synthetics like polyester, nylon, and rayon. As you might expect, synthetics are more damaging for the environment and more likely to be loaded with harmful chemical residues.

In addition to choosing a better fabric, it is wise to avoid curtains coated with stain treatments and flame retardants, as these chemical treatments off-gas VOCs into your home. Also, look for curtains that have been colored with less toxic, low-impact dyes, or opt for naturally pigmented fabrics such as color-grown cotton.

Curtains with a light-colored lining will help to reduced energy costs by deflecting the sun's rays in the summer and minimizing air leaks in winter. If your favorite curtains don't have linings, they can always be added later by a skilled seamstress.

Window Blinds and Shades

Faux wood and plastic blinds typically contain polyvinyl chloride (PVC), which has a pretty destructive environmental lifecycle. PVC releases carcinogenic dioxin into the air during manufacture (and after disposal, if it is incinerated), and it contains plasticizers called phthalates, which can trigger respiratory problems and interfere with the body's hormonal systems. In 1996, vinyl mini blinds were also found to contain lead, a neurotoxin used as a UV stabilizer that leaches out of vinyl blinds as they age. The Consumer Product Safety Commission asked the window-covering industry to switch to a safer stabilizer, and now an undisclosed tin compound is commonly used, according to the trade group Window Covering Safety Council.

If heat gain in the summer is your problem, wood shutters, preferably external, will do the most to cut your energy bills. But in either situation, you can increase the efficiency of your window by installing low-emittance (low-E) glazing, which you can find at most local hardware stores.