Blackout curtains were common during World War II, and were used to conceal the lights in homes and buildings from enemy pilots. They are not used exclusively for that reason today as they have become a big part of the decorating world. There are three main reasons why one may wish to use this heavy type of window dressing in their home: (1) to block light; (2) to lessen energy costs; (3) to block noise. The most common use for this type of curtain is to block the outside light from entering a room. One may wish to do this for various reasons. For those who work at night, making use of this type of curtain allows them to sleep during the day, with the illusion that it is nighttime in their room. Others use them in the nursery to keep the sunlight from waking their child too early, or to create a space conducive to sleep. They are also used in hospital rooms as well as in sleep clinics. In addition, for those who have a home theatre space, they are especially useful for maintaining the darkness in that room.

Using blackout lined curtains can also help to insulate one's home from either heat or cold. During the wintblackout lined curtainser, it is possible for up to 20% of the heat in one's home to be lost through the windows. Making use of thermal or lined drapes can help to keep the heat inside the home. In the case of hot weather, these lined drapes, besides keeping the sunlight out, also repel the heat, helping to keep the inside of the home cool. Thermal curtains used to block the light are usually limited to solid colors, but due to the abundance of colors available, they should be able to fit into most any type of décor. Those with a lining meant only for room darkening, without the thermal properties, come in solid colors as well as patterns.

Some homeowners use the lined window coverings to help block out sound. Especially for those who live within a city, these curtains and drapes are doubly helpful. They block light from coming through the window, allowing one to sleep better, as well as limit the amount of noise pollution that might enter through the window, due to the thicker thermal lining.

In addition to room darkening drapes, there are other window coverings which can be used to block light, although not always as effectively as the curtains and drapes above. These include blackout shades and blinds. The shades, which come on a roller, can help eliminate light entering a room from the outside, although they may not be as efficient as the fabric drapes. However, they are a practical choice for smaller windows. Blackout blinds usually come in wood, aluminum or faux wood. These window dressings work well when it is difficult to match a fabric window treatment with the décor of the rest of the room. Vertical blinds are also used to control the light in a room, but are not as effective as other blinds.

Depending on one's needs, there are several choices available when deciding which room darkening window treatment to use. With the added benefits of insulating a window as well as helping to cut down on noise from the outside, using blackout curtain linings in one's home can be very advantageous. With the range of styles and colors available, from drapes to wooden blinds to roman shades, one should have no difficulty finding the perfect match for their décor.