For extra protection, NFPA recommends that you also install detectors in the dining room, furnace room, utility room and hallways. If your family sleeps with bedroom doors closed, you might also install detectors inside the bedrooms. To install most smoke detectors, all you need is a screwdriver and a drill. Most smoke detectors operate on batteries or household current. A detector plugged into a wall outlet must have a restraining device so it cannot accidentally be pulled from the outlet.
Detectors can also be hard-wired into the electrical system.
Never hard-wire a detector to a circuit that can be turned off at a wall switch. Because smoke rises, mount the detector high on a wall or on the ceiling to detect the first traces of smoke. For a wall-mounted unit, the top of the detector should be 4 to 12 inches from the ceiling. A ceiling-mounted detector should be placed at least 4 inches from any wall. In a room with a high pitched ceiling, mount the detector on or near the ceiling's highest point.