First Alert SC5 Battery Smart Smoke & CO Alarm vs Heiman Smart CO Alarm

Both of these run on batteries, so hazard coverage and app reach make the call: the First Alert SC5 Battery Smart Smoke & CO Alarm wins by combining smoke and carbon monoxide sensing in one unit, sending a fuller set of alerts, and cutting nuisance alarms with steam-check technology, none of which the CO-only Heiman Smart CO Alarm includes. The Heiman Smart CO Alarm trades that for a lower price, a built-in flash light, and Matter-over-Thread integrations that reach Google Home, Alexa, Apple HomeKit, Samsung SmartThings and Home Assistant, well beyond the SC5 Battery's Google Home-only support. Both alarms are rated for roughly a decade on their replaceable batteries, so battery upkeep is a wash between them. Buyers who want a single battery-powered alarm covering both smoke and CO with steam-check tuning should get the First Alert SC5 Battery Smart Smoke & CO Alarm, while anyone who already has smoke detection and wants an affordable CO monitor that plugs into a Matter smart home should choose the Heiman Smart CO Alarm.