You should have at least one smoke detector in each bedroom, the hallway and at the top of all stairways. Smoke rises, so the best place to install a detector is on the ceiling or high on an inside wall approximately 6-8 inches below the ceiling. We recommend that you buy a battery-operated smoke detector that carries the Underwriter's Laboratories (UL) logo.
Newly constructed occupancies are required to have wired smoke detectors with battery backup that are all connected to sound simultaneously if one detector is activated. We recommend that you test your smoke detectors by pressing the test button monthly. If the detector fails to sound, replace the battery. Otherwise, we recommend that you replace all of your smoke detector batteries twice a year.
The best time to change your batteries is at the same time you set your clocks back and forth between Daylight Savings Time and Standard Time.