The BRK Electronics 9120B smoke alarm is a wired-in smoke alarm with battery backup, and these models offer plenty of peace of mind. At less than $30, this unit provides the benefit of a 9-volt battery back-up, as well as several other features that make it well worth the expense.

Smoke detectors that use ionization sensors are often criticized for generating false alarms, due to common smoke-producing accidents such as burning food, but this model uses several features to cut down on "nuisance alarms," including a redesigned cover, a metal sensing chamber, and an integrated circuit that looks at exactly what's causing the alarm before it starts to beep.

Designed to appeal to contractors, this model's Perfect Mount base makes installation easier, and its UV-resistant cover prevents discoloration over time, even if it's positioned in direct sunlight. But the BRK Electronics 9120B smoke alarm provides plenty of homeowner-friendly features, as well. It comes with a 10-year limited warranty.


Pros: Battery back-up, UV protection
Cons: Ionization sensor only

Warranty
10 years, limited