The First Alert SC5 is a smart combination smoke-and-carbon-monoxide alarm family, not one interchangeable product. The battery SMCO600NV (retail SKU FSMCO600NVCL1) and hardwired SMCO600NV-AC (SKU FSMCO600NVACCL1) solve different installation problems. Choose by power and interconnect requirements before considering app features.

Battery SC5

First Alert specifies photoelectric smoke sensing, electrochemical CO sensing, voice/location warnings, Wi-Fi, wireless interconnect, and an 85 dB horn at 10 feet for the battery SMCO600NV. It uses six replaceable CR123A 3-volt batteries. That battery count is a real maintenance obligation, and the alarm must not be left disabled while replacements are sourced.

First Alert’s compatibility page lists wireless compatibility with named SC5 models and second-generation Google Nest Protect when the required Google Home setup and account are used. Treat that list as exact: a similar brand name or app logo does not prove alarm-to-alarm compatibility.

Hardwired SC5

The SMCO600NV-AC is for a household-power installation with backup power and a named hardwire interconnect list. Confirm the existing circuit, connector, box, interconnect conductor, and every alarm model on the network. A plug that appears to fit is not enough. Use a qualified electrician when wiring or code compatibility is uncertain.

Smart features are supplemental

App status and remote notifications can be useful, but Wi-Fi, phones, permissions, cloud services, and accounts can fail. The local horn, code-compliant placement, regular testing, and an escape plan remain the safety system. A notification is not monitored fire response and should never delay evacuation or emergency calls.

USFA recommends smoke alarms inside and outside sleeping areas and on every level, with CO coverage also placed according to current guidance, the manual, and local rules. Keep alarms away from locations prohibited by the manual; poor placement can increase nuisance alarms or slow detection.

Verdict

The SC5 is worth considering for a home that specifically needs its combined detection and supported Google Home/interconnect path. Buy the battery version for an approved battery installation and the hardwired version only when the wiring and network match. Record installation dates, test as directed, respond to every alarm, and replace units at end of life.