Why does my carbon monoxide detector beep at night

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

Installing a carbon monoxide (CO) detector in residential and commercial buildings is extremely important, as it indicates the presence of this odorless, colorless, tasteless, and potentially fatal gas. An effective detector will sound a beeping or chirping noise to warn those inside to quickly leave the premises.

According to the most recent statistics from the Centers for Disease Control and Prevention (CDC): “Approximately 50,000 people in the U.S. visit the emergency department each year due to accidental CO poisoning.”

The agency adds that of those, more than 430 will lose their lives. 

To ensure a properly functioning CO detector, homeowners and business owners must periodically perform tests and inspections. The first indication of a potential issue is a beep or chirp—occurring anywhere between every 30 seconds to five minutes.

This could be one of two things.

A beeping or chirping CO detector could signify the presence of gas, or a low battery. Regardless of the reason, further action should be taken.

Below we’ll discuss how carbon monoxide detectors can protect your loved ones and property, and why it’s important to conduct regular device inspections, testing, and maintenance.

A beeping or chirping CO detector could signify the presence of gas, or a low battery. Regardless of the reason, further action should be taken.

How Do CO Detectors Work?

Powered by batteries or connected directly to residential and commercial electrical systems, CO detectors function via a silicon microchip, sensors, and semiconductors. Upon detecting this potentially fatal gas, they sound a beeping or chirping noise indicating potential danger. Detectors equipped with LCD screens also display CO levels and system statuses to indicate inspection deadlines.

CO detectors also signal noxious gas buildup, even before occupants experience symptoms. For example, low CO levels of approximately 50 parts per million (ppm) won’t trigger beeping for several hours, while 150 ppm sound detectors almost immediately.

CO Detector Beeping & Chirping Signals

It’s important to reiterate: Carbon monoxide can be fatal. Because CO detectors protect people from this dangerous gas, incessant chirping should signal occupants to immediately leave the residence or place of business. This deadly gas may be present, and fire emergency professionals should be contacted, immediately.

When listening for CO detector beeps or chirps, there are differences between patterns.

Note the following:

  • Four beeps accompanied by a pause indicate CO is present. Occupants should immediately seek fresh air and notify emergency personnel.
  • One chirp per minute means CO detector batteries are due for replacement.
  • Five beeps per minute signals the detector should be replaced.

CO Poisoning Symptoms & Exposure

According to the New York State Department of Health: "If you suspect CO poisoning, have everyone leave the area to get fresh air immediately. Contact the fire department and the gas company or heating contractor.”

The agency also recommends scheduling regular inspections of home heating sources, such as furnaces, fireplaces, and chimneys.

Watch for the following symptoms if you think you may have been exposed to CO:

  • Nausea 
  • Chest Pain
  • Dizziness  
  • Shortness of Breath

The American Association of Poison Control Centers is also available for medical advice on this and other potentially fatal situations. 


Regularly Maintain & Inspect CO Detectors

Although some CO detectors have replaceable batteries, units with 10-year-lifetime sealed lithium batteries will also beep as an end-of-life warning. It’s important to keep track of a CO detector’s age, and conduct regular testing, inspections, and maintenance.

If your CO detector has replaceable batteries, it’s recommended to change them every six months, or upon daylight saving time. CO detectors eventually run their course—most with shelf lives of five to seven years.

Best Places to Install CO Detectors

Whether for a small apartment or multi-room home, it’s recommended to place detectors on walls at least five feet from the ground. Optimal locations include bedrooms or other sleeping areas, and near gas fireplaces, ovens, and stoves. Consider installation in garages and sheds, or other spaces with gas-powered tools and vehicles.

Place CO detectors on each floor of commercial buildings, including within offices and other communal areas, such as kitchens, conference rooms, and cafeterias.

Alarm.com Mobile Alerts

Working with General Security for fire and safety technologies gives you access to the Alarm.com mobile app, as well as local authorities through 24/7 Central Station Monitoring. Real-time alerts are sent to any mobile device—whether regarding a carbon monoxide leak, or low or missing batteries. While you should always regularly test and inspect devices, such direct connections grant invaluable peace of mind—while preventing injuries and saving lives. 

Ensuring Health & Safety

Whether upgrading existing fire and safety measures or adding an entirely new system, consider working with a reputable provider such as General Security, for expert assistance with installation, monitoring, and inspections.


General Security provides advanced fire and safety protection measures for homes and businesses. Request a free quote from us today!

Why does my carbon monoxide detector only beep at night?

In conclusion, low battery levels and outdated detectors are the main reasons for midnight beeping of detectors. Low temperature on the other hand, only increases the chance of this happening. For this reason, replacing the battery or old detectors will help in preventing this from occurring.

Can carbon monoxide alarms go off for no reason?

Smoke and carbon monoxide (CO) detectors can false alarm for several reasons. False or nuisance alarms are when your smoke detector or CO alarm goes off, but there is no presence of smoke or carbon monoxide in your home.

What does a carbon monoxide alarm sound like when it's going off?

Listen for the Particular Sound of a CO Detector A carbon monoxide detector does not sound the same as a smoke detector. It sounds similar to the way a smoke detector beeps when it needs a battery replacement. It will beep at a regular rate to alert you of a carbon monoxide presence.

What can falsely set off a carbon monoxide detector?

A carbon monoxide (CO) detector false alarm may be caused by a few things including its proximity to fuel-burning appliances, exposure to humidity, or the low quality of the device itself. As the detector works to keep you and your home safe, the slightest environmental changes may cause more worry than peace of mind.