In stairways with no doors at the top or bottom, position smoke detectors anywhere in the path of smoke moving up the stairs. But always position smoke detectors at the bottom of closed stairways, such as those leading to the basement, because dead air trapped near the door at the top of a stairway could prevent smoke from reaching a detector at the top. Don't install a detector too near a window, door, or forced-air register where drafts could interfere with the detector's operation. Installation Most battery-powered smoke detectors and detectors that plug into wall outlets can be installed using only a drill and a screwdriver by following the manufacturer's instructions. Plug-in detectors must have restraining devices so that they can't be accidentally unplugged.
Detectors can also be hard-wired into a building's electrical system.
Never connect a detector to a circuit that can be turned off at a wall switch. False Alarms Cooking vapors and steam sometimes set off a smoke detector. Try moving the smoke detector farther from the kitchen or bathroom, or turn on an exhaust fan. Cleaning your detector regularly, according to the manufacturer's directions, may also help. Following the manufacturer's instructions, test all your smoke detectors monthly and install new batteries at least once a year.