We often think of curtains as just a decorative item. Yet they may be the hardest-working textile in a room.
Let us start with light. Sheer curtains diffuse light, softening harsh sun and giving privacy during the day. Blackout curtains block light almost completely, thanks to a special coating on the back or a very dense weave. For night-shift workers or nurseries they directly change the quality of sleep. Warmth matters too: a heavy, lined curtain holds back some of the heat escaping through the glass in winter, and slows the sun from heating the room in summer.
A side that is rarely discussed is sound. An empty, echoing room becomes noticeably quieter with heavy fabric curtains. When choosing, pay attention to fullness. Fabric two to three times the width of the window lets the curtain hang beautifully and perform all these functions properly. Finally, fibre choice matters for windows facing the sun. Cotton and silk weaken and rot over time under the sun's UV rays. Polyester is much more durable in this respect.