Current standards require functional Smoke Alarms to be installed on the ceilings of all bedrooms and their adjacent hallways, and at least one Smoke Alarm should be installed on each level of the house.
Smoke Alarms that use photoelectric sensing technology are superior to those that use ionization chamber sensing technology. Ionization alarms have proven themselves to be particularly prone to nuisance alarms, which tend to cause people to disable them. Those that are not disabled can fail to detect certain kinds of smoldering fires. Photoelectric alarms, in contrast, tend to be less susceptible to nuisance alarms and are dramatically superior at detecting smoldering fires, particularly those that involve synthetic materials. Smoke inhalation from smoldering fires is a far more common cause of death in home fires than exposure to flaming-mode fires.