The length of the curtains in a living room depends on the how the curtains must function and the style of the living room itself. Long, luxurious curtains puddling onto the floor enhance a very formal style of decor, while crisp, pleated curtains just skimming the floor enhance a more functional, modern room.
How do the curtains open and close? The weight of the curtains, including the fabric, interlining and lining together, should be considered. For ease of function, full-length curtains that end at least 1/2 inch above the floor work best.
If the curtains are to be hand drawn, they will require more frequent cleaning than if drawn by cords and pulleys. Full-length to the floor curtains should be dry cleaned, because the amount of fabric is generally too large for domestic washing machines to handle well. Curtains that touch the floor will require more cleaning than those that don't.
The effect of puddling drapery -- which is 12 or more inches of drapery in length -- can be very beautiful, but the functionality of this is limited. The curtains cannot be opened and closed easily, and cleaning the floor necessitates fastening the drapes up and possibly creasing them. The current trend of a break in the curtain is an offshoot of this older trend. Breaking curtains are usually 1 to 2 inches excess length and can be hand or cord drawn.
In a room with electric heat registers under the window, the curtains must be short enough to clear the registers. In a casual room, the curtains often stop just below the windowsill. Formal living rooms tend to require curtains to be full length or longer. If the floor in the room is not exactly level, curtains that just touch the floor could appear unevenly hemmed.