First Alert ZCOMBO-G Z-Wave Smoke/CO Alarm

Quick verdict

The ZCOMBO-G is a common pick for adding smoke and CO detection to a Z-Wave smart home. It reports alarm state locally to Home Assistant, enabling powerful automations like flashing lights or unlocking doors during emergencies. The catch is you need a Z-Wave coordinator, and the alarms do not interconnect with each other wirelessly. First Alert has since replaced the ZCOMBO line with the SMCO410, which keeps the Z-Wave Plus radio and the 2-in-1 detection but swaps the replaceable AA cells for a sealed 10-year battery. This page covers the 2nd-generation ZCOMBO, so compare the two before buying new.

Standout: One of the few smoke and CO alarms with Z-Wave support for fully local smart home integration without any cloud dependency.

Last checked: 2026-08-06

Compatibility snapshot

Why it stands out

• fully local Z-Wave alarm reporting with no cloud dependency whatsoever
• combination smoke and CO detection in one device at a reasonable price
• well-supported in Home Assistant via the Z-Wave integration for automations like turning on lights during an alarm

Reasons to hesitate

• requires a Z-Wave hub or coordinator to get smart functionality
• battery-powered Z-Wave devices can sometimes have delayed wake-up reporting
• no interconnect with other First Alert alarms over Z-Wave, each unit reports independently
• superseded: First Alert's own spec sheet lists the SMCO410 as the replacement for the ZCOMBO line, so this model is the outgoing one

Best for

• Home Assistant users who want local smart smoke and CO alerts for automations
• Z-Wave households that want to add life safety devices to their existing network

Avoid if

• you do not have a Z-Wave hub and do not want to invest in one
• you need interconnected alarms that all sound when one detects smoke

Privacy and local-control notes

Fully local Z-Wave device with no cloud component or internet requirement. Alarm state is reported directly to your Z-Wave hub.

Home Assistant support: supported · integration path: Z-Wave.

Buying reality check

Price notes: Priced similarly to premium non-smart smoke alarms. Uses standard AA batteries. Z-Wave hub sold separately. The newer SMCO410 replacement uses a sealed 10-year battery instead, which changes the long-run cost, so price both.

Compare side by side: see smoke alarm comparisons →