Carbon Monoxide Detector Beeping May Mean More Than Low Battery

Carbon monoxide detectors beep for a variety of reasons: low battery, malfunctions and actual emergencies.

If your carbon monoxide detector is beeping intermittently, grab a pair of AAA batteries or a 9V battery. The LED lights show the battery level. That said, we recommend changing the battery twice a year. When you change clocks for daylight saving time, change the battery in your carbon monoxide detector.

It might be time to replace the whole carbon monoxide detector if you change the battery and it’s still beeping. According to the National Carbon Monoxide Awareness Association, less than half of US families have a functioning carbon monoxide alarm. Do you want your home to be one with a working detector? You may need more than a new battery.

If you changed the battery and your carbon monoxide detector is still beeping, then:

• Check the detector’s age. If it’s older than seven years or you can’t find a date, get a new carbon monoxide detector.
• Reset the detector. Clear error codes by holding the test button to reset the detector. Test the detector to ensure the alarm is working.
• Check the detector hardware. Humidity, dust and loose power connections can cause a carbon monoxide detector to beep intermittently. Clean the sensor with compressed air. Check the power connections.

Store Associate Demarquis Kingsland-Parker knows which battery your carbon monoxide detector needs. | Courtesy photo: Jerry Whitt, Interstate All Battery Center in Selma, Texas

New batteries can solve the chirp sometimes. Interstate All Battery Center Store Manager Jerry Whitt leads a store in Selma, Texas. Every week, several customers visit his store. They want new batteries for smoke detectors and carbon monoxide detectors.

“They go off in the night. It always seems to be the middle of the night,” Whitt said. “We recommend the lithium 9V battery, but you can just do a traditional 9V battery. You’ve just got to remember to change it when the time changes.”

Often replacing the battery will stop your carbon monoxide detector from beeping intermittently.

What happens if a new battery doesn’t do the trick?

What It Means When Your Carbon Monoxide Detector Is Beeping

What do all the different long beeps and short chirps from your carbon monoxide detector mean?

Here’s a breakdown of the most common detector beeping patterns:

• Continuous loud beeping is typically the alarm. Carbon monoxide detectors beep four times when their sensor registers a significant amount of carbon monoxide in the air. This attention-grabbing alarm is usually four loud beeps with a pause.
• A single chirp every minute is typically the low battery alert. Carbon monoxide detectors beeping just once a minute is a non-emergency alarm and one of the most common: low battery. Even carbon monoxide detectors with a hardwired power connection have a battery that needs to be replaced. The battery is a backup in case of a power outage. The process to replace the battery isn’t too different from replacing a smoke detector battery.
• Beeping two or three times per minute may be a faulty sensor. Carbon monoxide detectors use sensitive gas-permeable sensors or metal oxides to detect harmful levels of the odorless, colorless gas. Humidity, power surges or dust may disrupt them. The detector can tell it’s not an emergency, even if something disturbed its sensor. Resetting the detector should clear the fault and keep your detector ready to go.
• Beeping more than three times per minute may mean you need to replace it. Carbon monoxide detectors last only five to seven years, and many are programmed to sound a special alert when they’ve expired and need to be replaced entirely. Swapping the battery won’t stop the beeping. You’ll need to purchase a whole new unit.

Signals can vary from unit to unit. Some detectors from Kidde will chirp twice when they’re at the end of their life, but a similar unit from First Alert will chirp five times. Look up the user manual from the manufacturer for your specific carbon monoxide detector’s signals.

RELATED: Four Things to Check If Your Smoke Detector Is Beeping.

What Kind of Batteries Does a Carbon Monoxide Detector Take?

Carbon monoxide detectors need AA batteries or a 9V battery. Whitt has seen some require a CR123A battery. That's a 3V lithium battery that’s about the width of one AA battery and half the height.

The surest way to identify which battery your detector needs is to pull it off the wall and match the battery there.

Some carbon monoxide detectors are hardwired for power, and even they have a battery that needs to be checked and replaced. Like hardwired smoke detectors, these units have a battery so they can still run in case of a power failure. (Before you disconnect any hardwired detectors, be sure to turn off the circuit breaker connected to that part of the house.)

The only real question can be whether you choose a lithium or an alkaline. The biggest difference is how long they last. Alkaline batteries will last about a year in a carbon monoxide detector while lithium batteries can last 10 years.

There’s a good case for choosing an alkaline battery.

Carbon monoxide detectors are low-drain devices. They draw a little power over a long time. Production and Engineering Manager Mike Harris knows batteries inside and out. He said both alkaline and lithium batteries work well in low-drain applications, so it may come down to your preference, “especially if you’re in the habit of changing them twice a year.”

That said, one of the most common causes to make a carbon monoxide detector beep is the low battery. If your detector is hard to reach, you may want to upgrade to the lithium battery.

“That’s what I’d go with,” Whitt said, “especially if you’ve got to get up on a ladder and your knees are shaking trying to reach it, you’re not going to want to do that every year.”

Some carbon monoxide detectors may come from the factory with a lithium battery inside, meaning it’ll last the full lifespan of the detector. In Whitt’s experience, some detectors are designed so that the customer can’t replace the battery. Those are made to be discarded as soon as the sensor goes bad, which may be seven years.

If you have a recreational vehicle, don’t forget to check the carbon monoxide detector in there, too. If your RV doesn’t have a carbon monoxide detector, consider installing one.

Carbon monoxide can collect when you’re cooking with propane or gas stoves. That makes travel trailers, fifth wheels and any other campers a natural place for carbon monoxide to collect.

Of course, the carbon monoxide detector may run out of power, collect too much dust or simply expire when you’re not using the RV. When you’re changing clocks and checking on the smoke alarms and carbon monoxide detectors in the house, make sure you take a moment in the RV to see if any detectors are beeping there, too.

How to Change Batteries in Carbon Monoxide Detectors

1. Detach the unit from the wall.
2. Switch the dead battery with a new one.
3. Test the alarm to make sure your carbon monoxide detector works.

For your own safety, flip your circuit breaker before removing a hard-wired carbon monoxide detector. You’ll see how to access the detector’s battery when you pull the unit from the wall. It may be a pull tab, a drawer or simply connectors holding it in place.

You may also find corrosion near the battery terminals. Cleaning corrosion is easy. Use a cotton swab, baking soda and water to wipe the terminals.

Interstate Batteries takes home safety seriously.

That’s why Whitt and other store managers work with fire chiefs and fire departments. They offer batteries and support during home hazard awareness campaigns.

Carbon monoxide detectors should be on every level of your home. They should also be placed near furnaces, water heaters and fireplaces. Any natural gas or propane-powered appliances could be a source of carbon monoxide.

A chirping carbon monoxide detector can disturb a peaceful afternoon, sure. Even so, it’s important to resist the temptation to leave a smoke or carbon monoxide detector disabled.

Why Do Carbon Monoxide Detectors Expire?

Detecting dangerous levels of carbon monoxide is harder than sensing smoke. That’s not just because it’s an odorless, colorless, tasteless gas.

Carbon monoxide is everywhere. The molecules are also much smaller than the soot particles in smoke.

A variety of chemical sensors make it possible to detect harmful gas levels. Gas-permeable sensors or metal oxides in the circuit react to carbon monoxide. That reaction tells the circuit that there’s too much of the harmful gas.

These sensors degrade over time.

Humidity around the detector, temperature swings and dust can interfere with the sensor. They’re also sensitive to high temperatures, just like car batteries. If an area is too hot or too humid, the sensors may degrade faster than usual.

Manufacturers such as First Alert and Kidde recommend replacing carbon monoxide detectors every five to seven years. (Smoke alarms should be replaced every 10 years.)

That’s why you should note the expiration date when you replace or test the battery on your carbon monoxide detector. If it’s five years old, consider shopping for a new detector. If you forget, don’t worry. The detector will alert you that it’s time to get a new one.

Gas stoves, car engines and fireplaces can produce carbon monoxide. That harmful gas can’t dissipate unless you have enough ventilation.

When you can’t see, smell or taste the danger, it helps to have a working carbon monoxide detector watching out for you, powered by an Outrageously Dependable battery.