Install smoke alarms that are Underwriter Listed (examined and tested to appropriate product safety standards) by a qualified testing laboratory on every level of your home, including the basement (but not unfinished attics). Make sure there is an alarm in or near every sleeping area.
Mount the smoke alarms high on ceilings or walls – remember, smoke rises. Ceiling-mounted alarms should be installed at least four inches away from the nearest wall; wall-mounted alarms should be installed four to 12 inches away from the ceiling.
Don't install smoke alarms near windows, outside doors, or ducts where drafts might interfere with their operation.
Don't paint your smoke alarms; paint or other decorations could keep them from working when you most need it.