Smoke detectors are used to detect airborne smoke and emit alarms to alert homeowners of possible fires. They are usually installed rooms with high-risk heating or electrical devices, such as furnaces, chimneys, and electric or gas-powered appliances. They are usually installed on walls or ceilings, and can run on batteries or connect to the home’s electric system.
Smoke detectors may be used alone, integrated into home security systems, or installed in several rooms. Multiple smoke detectors are often interconnected so that smoke in one room can trigger all the other units. Some alarms are also accompanied by flashing lights to alert hearing-impaired users.