Smoke detectors have been shown to save lives in the event of a structural fire. The effectiveness of a smoke detector depends on where it is placed.
Smoke detectors should be placed outside each door in the room. This allows the detector to do its work and wake up every resident in the case of a fire.
Smoke detectors should be placed in the bedroom when the doors are closed on a regular basis. This is especially important if you smoke in bed. Locked doors can prevent heavy sleep to not hear the alarm and can keep the smoke from a fire in the bedroom of reaching the detector. read: smoke detector coverage area.
If only one detector is used, it must be installed in the hallway between rooms to maximise the chances that someone is going to listen to the alarm and alert others. If the House has several levels, there must be at least one sensor per plant.
Do not put detectors near heating ducts, as the heat can cause detectors are turned off accidentally. Ventilation can also keep the smoke reaches the detector, avoiding to get out.
It is suggested a minimum of a detector by sleeping area so that an alarm is located so close to sleeping possible.
