The First Alert SC05 Combination Smoke and CO Alarm operates as if it was two separate units, and relies on two independent sensors to monitor the air.

Combination smoke and carbon monoxide alarms are often a good, space- and money-saving idea, particularly if it's easy to distinguish between the two threats in the middle of the night. And the First Alert SC05 combination smoke and CO alarm does indeed provide two distinct alarms, one for smoke (three long beeps) and one for CO (four short beeps).

The smoke detector on the First Alert SC05 utilizes photoelectric technology, which tends to reduce false alarms; photoelectric detectors like this one are often less sensitive to cooking mishaps or other non-emergency fires than units that rely on ionization. The CO detector, like most others, is electrochemical.

This unit comes with two AA batteries, which can be loaded into a fairly easy-to-slide drawer. The unit features a test button, which can also be used to silence the alarm.

The First Alert SC05 combination smoke and CO alarm is an effective unit that offers double protection in a single model.


Pros: Separate alarms, photoelectric smoke detector
Cons: No digital display

Warranty
5 years, limited