November 2, 2026 — A consumer has reported persistent malfunctions with First Alert/Resideo smart smoke and carbon monoxide (CO) alarms, spanning two product generations over five years. After replacing problematic Onelink detectors with SC5 models, the homeowner experienced seven false alarms in five months, with unresponsive mute functions, leading to disconnected units and an under-protected home.
Product Details
Product: SC5 Battery Smart Smoke and Carbon Monoxide Alarm SMC0600NV-A
Incident Overview
The incident details a troubling five-year history of product failure and customer service interactions involving a consumer and Resideo LLC, the manufacturer of First Alert branded safety products.
In January 2021, the consumer initially purchased Onelink smart smoke and CO detectors for $810.72. By October 2021, the first claim was opened due to persistent false alarms. Steps to avoid false alarms were provided but no action was taken on the part of First Alert. Despite performing suggested cleaning, maintenance, and placement, the false alarms continued for two years. A second claim in August 2023 resulted in First Alert sending out 1 replacement unit. False alarms from multiple units continued.
The situation came to a head in February 2026 when a third claim was opened. Resideo sent out 8 replacement units. First Alert acknowledged widespread failures and the discontinuation of all Onelink units, subsequently sending eight SC5 Battery Smart Smoke and Carbon Monoxide Alarm units as replacements in March 2026.
However, the safety issues were far from resolved. Between June and October 2026, the newly installed SC5 units generated seven false alarms within a span of five months. Crucially, during these incidents, the mute function in the accompanying app was frequently unresponsive, and even pressing the physical button on the alarm failed to silence it. This ongoing malfunction forced the consumer to disconnect three of the SC5 units, leaving their home under-protected. The reported false alarms occurred on:
Jun 5: 12:21 AM EST
Jul 19: 10:46 AM EST
Aug 5: 11:08 PM EST
Aug 21: 2:48 AM EST
Aug 23: 10:20 AM EST
Sep 8: 8:44 AM EST
Oct 6: 5:59 PM EST
Extensive user documentation cited by the consumer indicates that the SC5 line has known firmware defects, particularly during self-checks, and issues with app lockouts preventing the silencing of clear-air alarms.
The consumer’s request for a full refund of their original $810.72 purchase, citing two consecutive generations of product failure and the inadequacy of further replacements, was formally refused by a Resideo Customer Care Lead. Resideo reportedly claimed the SC5 replacements were a “goodwill gesture” and carried no warranty, despite failing within 120 days of installation and less than a year of manufacture.
Safety Concerns
This incident highlights several significant safety concerns for consumers:
- Immediate Dangers: When smoke and CO alarms are disconnected due to incessant false alarms, the home is left without critical protection against actual fires or carbon monoxide leaks. This drastically increases the risk of injury, death, and severe property damage in the event of an emergency. If the SC5 line indeed suffers from firmware defects during self-checks, there’s a risk that the alarms might not function correctly even in the presence of real smoke or carbon monoxide, failing to alert occupants to life-threatening conditions.
- Long-Term Risks: Persistent false alarms can lead to alarm fatigue, where occupants become desensitized to the sound of an alarm. This can result in delayed responses or even ignoring a genuine emergency, putting lives at risk. Frequent false alarms, especially at inconvenient times like the middle of the night, cause significant stress, sleep deprivation, and disruption to daily life for the household.
- Who Might Be Affected: All occupants of the home, including children, elderly individuals, or those with mobility issues, are at increased risk when safety systems are compromised. The ongoing disruption and stress affect the mental well-being of the household.
- Property Damage Potential: A home without functional smoke and CO alarms is highly vulnerable to extensive property damage or complete loss in the event of an undetected fire or carbon monoxide leak.
What Consumers Should Do
Consumers who own First Alert Onelink or SC5 Battery Smart Smoke and Carbon Monoxide Alarms should take the following steps:
- Verify Product Operation: Regularly test your smoke and CO alarms according to the manufacturer’s instructions.
- Address False Alarms Promptly: If you experience false alarms, follow troubleshooting steps such as cleaning the unit or checking for environmental factors (e.g., steam, dust).
- Do Not Disconnect Permanently: While temporary disconnection might be necessary during a false alarm, ensure units are reconnected immediately. If false alarms persist, contact the manufacturer for support or consider replacing the unit. Disconnecting alarms permanently leaves your home unprotected.
- Check for Firmware Updates: If your SC5 units are smart alarms, check the manufacturer’s app or website for any available firmware updates that might address known issues.
- Document Everything: Keep detailed records of purchase dates, incident dates and times (especially false alarms), communications with the manufacturer (including case numbers, names, and dates), and any troubleshooting steps taken.
- Report Incidents: If you experience similar issues with false alarms, unresponsive features, or other malfunctions, report the incident to the U.S. Consumer Product Safety Commission (CPSC) at www.SaferProducts.gov. This helps safety experts identify patterns and potential widespread defects.
Manufacturer’s Response
According to the incident report, Resideo LLC formally refused a full refund for the consumer’s original purchase of $810.72. The manufacturer reportedly stated that the SC5 replacement units were sent as a “goodwill gesture” and therefore carried no warranty, despite their subsequent failure within a short period after installation and less than a year from their manufacture date. This response is a point of contention within the incident report, highlighting a dispute over warranty and refund policies concerning defective replacement products.
Legal Help Available
If you or a loved one has been injured by a defective product or suffered property damage due to a product malfunction, you may be entitled to compensation. The experienced product liability attorneys at Farzan Law understand the complexities of defective product cases and can help you navigate the legal process. Farzan Law is a California based Personal Injury law firm focusing on protecting the rights of those wrongfully injured.
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Note: This information is based on incident reports provided by the U.S. Consumer Product Safety Commission. If you find information that is incorrect, please contact us immediately so we can correct the post to reflect accurate information.
Disclaimer: The information provided in this post is not intended to be legal or medical advice. This article is based on publicly available incident reports. The incidents mentioned have not necessarily been independently verified or adjudicated.