First Alert CO615 Review

Best stand-alone carbon monoxide detector

  • Versatile installation
  • Battery backup
  • Extremely loud horn
  • Seven-year limited warranty
  • CO level is not continuously displayed
  • Does not interconnect with other CO detectors

Bottom line

In situations where an interconnected CO detector alarm is impractical or impossible, a stand-alone CO detector like the First Alert CO615 is the next best thing. AC powered, it can plug directly into any outlet, though a better choice is using the included 6-foot power cord to mount it high on a wall per expert recommendations. It's very good or better at detecting CO levels, and the LCD display -- though not continuously on -- is informative.

Breaking it down


Good protection for a room or apartment Professional testers give the First Alert CO615 good grades, citing its ability to detect high and low carbon monoxide levels (though it's slightly better at the former). This is an AC-powered detector, but includes a battery back-up for continuous protection even when the power is out. The presence of the large LCD readout can be a little misleading. It comes into play during testing or an alarm, but does not display continuous CO levels. Peak CO levels can be recalled, but only from the previous 24 hours. The ability to connect to other alarms is missing, and that's a shortfall according to most experts, but the First Alert CO615 is still an able performer for room by room protection, such as for a bedroom while sleeping, or for smaller residences, such as apartments.

Ease of use

Installation is a breeze. Most owners say the First Alert CO615 is easy to install, test and use. It can plug into any outlet, but there's an included six-foot cord that lets you mount the detector high on a wall, per experts' recommendations -- though no less than 4-inches from the ceiling. Some advertising copy still mentions a feature that lets you silence the alarm with a standard remote -- like the one you use for your TV -- but that feature proved to be problematical, and is no longer offered on this alarm. The display only shows CO information during an alarm, or when checking peak CO levels over the past 24 hours, but does continuously display battery information. Though AC operated, the alarm uses batteries for backup power in case of a power outage. The alarm will not operate without those batteries in place -- something that's required for continuous protection, though still a source of some owner disappointment. The unit's horn is rated at 85 decibels within 10 feet, loud enough to wake up even the soundest sleeper.


Lasts seven years. The CO615 is covered by a seven-year limited warranty. An end-of-life alert will sound when the unit needs to be replaced. Some find the construction to be flimsy, others claimed that they received defective units. These are more than outweighed by users that express no such concerns, however.

Where To Buy
First Alert CO615 Dual Power Carbon Monoxide Plug-In Alarm with Battery Backup and Digital Display

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First Alert CO615 Reviews

1. includes the First Alert CO615 among the stand-alone alarms it tests. Ratings are given for the ability to test high levels of CO (300 ppm), low levels (150 ppm) and the quality of its display. An overall rating is also assigned and CO detectors of the same type are ranked to make it easy to see which one is best.

Review: First Alert CO615, Editors of, Not Dated


About 825 owners review the First Alert CO615 at, where it earns an overall rating of 4.4 stars. Complaints from owners who give low ratings center on build quality or confusion over usage and features. Those are more than made up for by owners that report that they are mostly to completely pleased.

Review: First Alert CO615 Carbon Monoxide Plug-In Alarm with Battery Backup and Digital Display, Contributors to, As of March 2014


Nearly 75 people reviewed the First Alert CO615 at Walmart's site, where it earns a 4.4-star rating. A handful say that the alarm either arrived defective, with dead or nearly dead batteries, or that it is poorly made with a battery door that fails to close securely. However, the majority are happy and around 92 percent say that they would recommend the CO detector to a friend.

Review: First Alert CO615 Plug-In With Battery Backup Carbon Monoxide Detector With Digital Display, Contributors to, As of March 2015


The First Alert CO615 is the only carbon monoxide detector reviewed on this opinion website. Roughly 40 people leave feedback, giving it an overall score of 89 out of 100. Generally, owners compliment its effectiveness and ease of use.

Review: First Alert Carbon Monoxide Plug In Alarm with Battery Backup and Digital Display #CO615 Reviews, Contributors to, As of March 2015

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