Google Nest Protect uses a custom, dual-wavelength Split-Spectrum smoke sensor, a redesigned smoke chamber, and an exclusive smoke algorithm to cut down on nuisance alarms.
Photoelectric smoke alarms work by using light to "see" tiny smoke particles given off by a fire. When smoke alarms are on the lookout for smoke in the air, they sometimes sound the alarm when they see things like dust, bugs, and steam. It's an industry-wide issue: the National Fire Protection Association estimated that fire departments responded to 16 false alarms for every 10 fires. And it's one of the issues we wanted to address with Nest Protect.
That's why the 2nd generation Nest Protect was designed with nuisance alarms in mind. Nest Protect uses several tools to help cut down on false alarms, while always remaining sensitive enough to detect real fires:
1. Redesigned smoke chamber and Split-Spectrum Sensor
Nest Protect is the first residential smoke alarm to use dual-wavelength smoke sensing. To reduce false alarms, the Split-Spectrum Sensor is encased in a redesigned smoke chamber that is shielded against outside light, etched to protect it against dust, and encased in a stainless steel screen. The screen has a hexagonal pattern that is designed to keep out bugs and fibers, while still allowing smoke to flow in.
2. Rigorous testing
Smoke alarms are tested to ensure they can alarm when there's a fire and that they're durable enough to work in the real world. Nest Protect passed all the tests it had to pass for certification in the U.S., Canada, and Europe – but then we went further, and designed our own tests to see how Nest Protect did when exposed to dust and bugs. And once Nest Protect showed it could work in a lab, we tested it in real life homes.
3. Steam CheckNest Protect uses a humidity sensor and custom algorithms to help tell the difference between smoke and steam. It's called Steam Check, and we estimate that it reduces false alarms from steam by 57%.