Why Is Your Carbon Monoxide Detector Beeping and What Should You Do?

Editor’s Note: This blog post was originally published in October 2018 and has been revised to reflect industry updates.

Carbon monoxide (CO) is an odorless, colorless, tasteless, and potentially fatal gas produced by the incomplete combustion of fuel-burning appliances. A carbon monoxide detector sounds a beeping or chirping alarm to warn occupants of its presence — or to signal a low battery or end-of-life condition.

Installing a carbon monoxide detector in residential and commercial buildings is one of the most critical safety steps a homeowner or business owner can take. The gas is invisible, odorless, and gives no warning to human senses — which is exactly why a functioning detector is the only reliable line of defense.

Unintentional carbon monoxide exposure accounts for more than 100,000 emergency department visits, 14,000 hospitalizations, and approximately 400 deaths annually in the United States.
Source: StatPearls, National Library of Medicine (NIH) — Last updated April 19, 2025 — ncbi.nlm.nih.gov/books/NBK430740

The most important thing to understand about CO poisoning is that deaths from exposure are preventable with the right equipment, properly maintained. That starts with knowing what your detector is telling you.

What Causes a Carbon Monoxide Detector to Beep?

A CO detector beeping signals one of two things: carbon monoxide has been detected in the air, or the device needs attention — a low battery, a malfunction, or an end-of-life warning. Both require immediate action.

The CDC identifies the most common sources of carbon monoxide in the home as furnaces, kerosene heaters, vehicles idling in garages, stoves, lanterns, gas cooktops, portable generators, burning wood, and charcoal. In confined or semi-confined spaces, CO from these sources accumulates quickly and can reach lethal concentrations within minutes.

A beeping or chirping detector could indicate the presence of gas or a low battery. Regardless of the cause, further action must be taken immediately.

How Does a Carbon Monoxide Detector Work?

Carbon monoxide detectors function via a silicon microchip, sensors, and semiconductors. Upon detecting CO gas, they sound a beeping or chirping alarm. Models with LCD screens also display CO levels in parts per million (ppm) and system status information.

CO detectors also signal noxious gas buildup before occupants experience symptoms. The concentration level determines how quickly the alarm sounds: low CO levels of approximately 50 parts per million (ppm) won’t trigger a beep for several hours, while 150 ppm sounds the alarm almost immediately. This graduated response gives occupants time to act before reaching dangerous concentrations, but only if the detector is functioning properly.

CO detectors are powered by batteries or connected directly to residential and commercial electrical systems.

What Do the Different CO Detector Beep Patterns Mean?

Each beep pattern signals a different condition. Learn what yours means before an emergency happens.

• Four beeps, then a pause — Carbon monoxide detected

  CO is present. Occupants should immediately seek fresh air and contact emergency personnel. Do not re-enter the building until it has been cleared.

• One chirp per minute — Low battery

  The CO detector battery needs to be replaced. Replace immediately and test the unit to confirm it is functioning.

• Five beeps per minute — End of life

  The detector has reached the end of its operational lifespan and must be replaced. Most CO detectors last five to seven years.

What Are the Symptoms of Carbon Monoxide Poisoning?

If you suspect CO poisoning, get everyone out of the affected area to breathe fresh air immediately. Then notify the fire department and contact your gas company or heating contractor. Do not wait for symptoms to worsen before leaving.

The New York State Department of Health advises that CO poisoning symptoms can be mistaken for flu or food poisoning, making them easy to dismiss. Watch for:

• Nausea

• Chest pain

• Dizziness

• Shortness of breath

Where Should Carbon Monoxide Detectors Be Installed?

CO detectors should be installed on every level of a home or commercial building, approximately five feet above the floor. Priority locations include sleeping areas, rooms near gas appliances, garages, and any space housing fuel-burning equipment.

For both apartments and larger homes, position carbon monoxide detectors near bedrooms and sleeping areas, adjacent to gas fireplaces, ovens, and stoves, and in garages or sheds housing gas-operated tools and vehicles.

In commercial buildings, install detectors on every floor — with priority placement in office spaces, kitchens, conference rooms, and shared communal areas.

How Often Should You Test and Replace a CO Detector?

Regular maintenance is non-negotiable. CO detector batteries should be replaced every six months — ideally during daylight saving time transitions. Most detectors have an operational lifespan of five to seven years and must be replaced at end of life, even if they appear functional.

Some units are equipped with 10-year sealed lithium batteries that emit an end-of-life beep when the unit needs to be replaced entirely. Regardless of battery type, be aware of your detector’s age and perform consistent testing, inspections, and maintenance.

When integrated with smart home security systems, smart thermostats can automatically shut down HVAC vents when a CO or smoke event is detected, helping prevent further spread of dangerous gas through the home.

How Does Alarm.com Integration Improve CO Detection?

Working with General Security gives homeowners access to the Alarm.com mobile app and 24/7 Central Station Monitoring — meaning a carbon monoxide alert triggers an immediate real-time notification to your phone and to a trained monitoring operator who can dispatch emergency services on your behalf, even if you’re not home.

Real-time mobile alerts are sent to any connected device for CO detection events, low or missing battery warnings, and device malfunctions. This direct connection ensures you’re notified the moment something is wrong — not after the fact.

How Do You Upgrade Your CO Detection and Home Safety?

Whether you’re upgrading existing fire and life safety systems or adding protection for the first time, working with an experienced provider ensures proper installation, monitoring, and ongoing inspections.

General Security provides advanced carbon monoxide detectors, smoke alarms, and fire and life safety systems for homes and businesses throughout the U.S., monitored 24/7 through a TMA Five Diamond-certified central station. Request a free quote or call us today.