Why this made the list
A smoke and CO alarm is one of the few smart home devices where the "smart" part is genuinely useful rather than a gimmick: getting a phone alert when nobody's home to hear the alarm actually matters. This model pairs that with real safety certification, which matters more here than in almost any other product category on this site.
What it actually does
It's a combination smoke and carbon monoxide alarm, certified to UL 217 (smoke) and UL 2034 (CO) standards, using a photoelectric sensor for smoke and an electrochemical sensor for CO. This version is hardwired into household electrical, with a 10-year sealed lithium battery as backup if the power goes out, so there's no annual battery swap. It connects over WiFi and Bluetooth to send push notifications to your phone through the Onelink app, along with voice alerts that announce the type and location of the danger instead of just a generic siren. It can interconnect with other Onelink alarms and compatible traditional hardwired alarms, up to 18 devices total, so if one triggers, they all sound. It works with Amazon Alexa and Apple HomeKit for status checks, though full voice control through Alexa isn't supported.
Who this is actually for
Anyone replacing an aging hardwired smoke detector who wants phone alerts and voice-announced alarms without adding a separate hub. It's particularly useful for households that travel or aren't always home, since a phone notification catches what an audible-only alarm can't.
What to weigh before buying
- This is the hardwired version, which means installation involves working with existing household wiring, not a plug-and-play battery unit. Some buyers will want an electrician for the swap.
- Push notifications depend on a working WiFi connection. If the network is down, you lose the phone-alert feature, though the local alarm and voice announcement still work.
- Full Alexa voice control isn't supported, only status checks, so don't expect to ask Alexa what triggered the alarm.
- Like any interconnected system, getting the full benefit means replacing multiple alarms in the home at once rather than swapping just one.
The verdict
A properly certified smoke and CO alarm that adds real value with phone alerts and voice location announcements, as long as you're prepared for a hardwired install and understand the WiFi dependency for notifications.