The National Fire Protection Association (NFPA) recommends that smoke alarms be installed on every level of the home, inside every bedroom, and outside every sleeping area. Keep alarms away from drafts caused by fans or air ducts, as this could blow smoke away from the sensor. The NFPA also recommends that you test your alarms at least once a month, and replace the batteries every six months, or as soon as a low battery chirp is heard. For more information about smoke alarm safety, visit nfpa.org.