Carbon Monoxide Detector Going Off? Here's What to Do Next

Key takeaways:

• Carbon monoxide are important home safety tools that detect dangerous levels of carbon monoxide in your home.
• If your CO detector goes off, leave the building, call 911, and do not re-enter the home. Wait for emergency services to give you the all-clear.
• If your carbon monoxide detector is beeping, always treat it seriously. Do not assume it is a false alarm.

CO detector basics

Carbon monoxide detectors are extremely important home safety tools. They can save your life by telling you when dangerous levels of toxic gas are in your environment, such as a carbon monoxide leak. But you might have questions about what to do when your carbon monoxide detector goes off.

It's important to have a plan to keep you and your family safe. You likely already have an action plan in the event your smoke detector goes off; having a plan in case your carbon monoxide detector senses unsafe chemicals in your air is just as important.

This guide reviews what to do if your carbon monoxide detector ever goes off. We'll explain what carbon monoxide (CO) is and some of the dangers of carbon monoxide poisoning. We'll also give you an overview of how your CO detector works to detect carbon monoxide in your environment.

What to do when your carbon monoxide detector goes off

Here's what to do when your CO alarm goes off:

1. Leave the building. Round up your family members and pets and seek fresh air immediately.
2. Dial 911 right away. Let emergency responders know your CO alarm has been activated.
3. Don't re-enter the home. The danger may still be present even if the alarm has ceased. Opening doors and windows will allow the CO in your home to dissipate, but you don't know if the machine that triggered the alarm has stopped producing carbon monoxide, so it is important to leave the windows open until you have the all clear.
4. Wait for emergency services to give you the all-clear. Only re-enter the home once the cause has been identified and emergency services have told you it's safe.

Do not ignore or reset the alarm

If your carbon monoxide detector is beeping, don't assume it's just a false alarm or system glitch. A carbon monoxide alarm is designed to alert you when even low levels of CO gas reach dangerous thresholds—and that warning should always be taken seriously.

Some homeowners may be tempted to hit the reset button or wait for the alarm sounds to stop. But unlike smoke, carbon monoxide can't be seen or smelled, so it's impossible to know whether your home is safe without proper testing by emergency services.

While false alarms can happen—usually due to dust, expired sensors, or placement near gas appliances—they're uncommon. And even in rare cases, it's safer to assume the detector is working correctly. Leave the home, call 911, and don't re-enter until emergency responders confirm it's safe.

What is carbon monoxide?

Carbon monoxide (CO) is a deadly, odorless gas produced when burning carbon-based fuel. Stoves, water heaters, fireplaces, vehicles, and a variety of other appliances and machines can create CO. It's known as the "silent killer" because humans can't detect it without a device.

Whenever carbon-based fuels like natural gas burn, they release carbon monoxide as a byproduct of incomplete combustion. Some fuels, like wood or propane, are considered low-carbon fuels because they emit lower levels of carbon monoxide into the air than natural gas.

Different types of machines produce different amounts of carbon monoxide, which is measured in parts per million (ppm). For example, starting your car can create CO levels of around 80,000 ppm for the first few minutes your engine is running.

To put that number in perspective, The National Fire Protection Association (NFPA) claims that air levels of just 400 ppm can cause headaches and nausea in as little as an hour. That's why you should never start your car in an enclosed space (like your garage with the door closed).

Meanwhile, your home's appliances burn fuel inside, where the CO gas has less room to dissipate. So, there are rules for how much CO your appliances can emit. For example, stoves aren't allowed to produce more than 800 ppm of CO. However, most stoves are designed to release below 50 ppm.

Fuel-burning appliances that have been left on too long or haven't been properly installed for ventilation by a qualified technician can continuously release small amounts of carbon monoxide into the atmosphere until they reach dangerous levels.

Carbon monoxide-producing appliances include:

• Furnaces
• Dryers
• Gas ranges (stoves)
• Wood-burning stoves (lower amounts than natural gas stoves)
• Boilers
• Ovens
• Cars and trucks
• Grills
• Space heaters
• Cigarettes or tobacco smoke

What are the symptoms of carbon monoxide poisoning?

Breathing in carbon monoxide prevents your blood from carrying enough oxygen to your cells. It can be hard to determine when you've been exposed to high levels of CO gas because the effects of CO can be similar to flu-like symptoms.

Below are some common CO-poisoning symptoms:

• Headaches, dizziness, or lightheadedness
• Fatigue
• Nausea
• Vomiting
• Blurred vision
• Diminished muscle control
• Chest tightening or elevated heart rate
• Extreme sleepiness, possibly to the point of loss of consciousness
• Disorientation or confusion

How carbon monoxide detectors work

Your carbon monoxide detector can sense when CO in your home reaches dangerous levels. An alarm sounds whenever it senses high levels of the toxic gas. If you hear your carbon monoxide detector beeping, that's your cue to get out of the house right away.

The speed at which your CO alarm can detect carbon monoxide depends on how much harmful gas is present. For example, if there's less than 70 ppm of CO in your home, it might take your CO detector around an hour to sound the alarm. If CO levels in your home are above 400 ppm, you might hear an alarm in less than five minutes.

CO detectors can be battery-powered (like the Vivint CO Detector and Smoke Detector) or connected to your electrical system. A silicon microchip is placed inside carbon monoxide detectors that is surrounded by hard plastic. The microchip shoots an electrical signal to a carbon monoxide sensor in a detection chamber.

CO Detectors measure CO levels in an area. When a CO detector notices high levels of CO, it activates the alarm.

CO detector features your model might have include:

• Test button for regular checks
• Light or chirping sound that indicates low battery
• LCD screen displaying the amount of CO gas in the atmosphere

Carbon monoxide detector best practices

To ensure a well-functioning CO detector that provides accurate protection for your home, follow these guidelines:

• Test your detector once a month using the test button.
• Replace batteries (or the entire unit) as needed, typically when the power indicator light shows or the device chirps.
• Replace CO detectors after about 5-7 years.

• Place CO detectors at least 20 feet away from the kitchen to avoid false alarms.
• Keep detectors 5-20 feet away from fireplaces and other appliances that use fire.

Where should carbon monoxide detectors be installed in the home?

Proper placement of carbon monoxide detectors is essential for early detection and reliable protection. CO gas mixes with air and can accumulate in various parts of the home, especially near fuel-burning appliances or sleeping areas. Here's where to install them:

• Near sleeping areas. Place a CO detector outside every bedroom or sleeping space. This type of installation ensures that if dangerous levels of CO build up while you're asleep, the alarm sounds can wake you.
• On every level of the home. Install at least one carbon monoxide alarm on each floor, including the basement. CO can move through floors and walls, so whole-home coverage is key.
• Close to fuel-burning appliances. Install CO detectors within 5-20 feet of common sources like furnaces, water heaters, fireplaces, and gas ranges. Avoid placing them directly above or beside these appliances to prevent false alarms.
• At least five feet off the ground or on the ceiling. Because CO gas is slightly lighter than air, it rises and mixes with warm air. Mounting detectors at this height will improve accuracy.
• Avoid high humidity or enclosed spaces. Don't install detectors in bathrooms, near vents, or in garages where natural gas or fumes may cause temporary spikes.

For the best results, always follow the manufacturer's instructions specific to your model, and test your detectors monthly by using the test button.

Carbon monoxide detector FAQs

Understanding how carbon monoxide detectors work is important to the safety of everyone in your home. Below, we've answered some commonly asked questions about CO detectors.

Why is my carbon monoxide detector going off for no reason?

There are a number of reasons you might get a false alarm from your CO detector:

• Your CO detector needs to be replaced.
• Your system detects a carbon monoxide leak from one of your neighbor's appliances.
• Your shower isn't properly ventilated, and steam is causing false alarms.
• You're using a lead-acid battery charger.
• You have the wrong type of CO monitor for your living space.
• Someone's smoking tobacco in your home.

Do carbon monoxide detectors give false alarms?

CO detectors can give off false alarms, especially if they're not handled properly. Here are some tips to reduce the number of false alarms your detector sets off:

• Test your detector every month.
• Change the batteries in your detector regularly (at least every six months).
• Clean your detector with a soft vacuum brush and compressed air every month. Don't use water or cleaning chemicals on your device.
• Install your detectors away from kitchens, fireplaces, and fire-producing appliances.
• Replace your detectors at least once every five to seven years or immediately if they get contaminated with heavy dirt or grime.

Should I worry if my carbon monoxide alarm goes off?

For safety, always assume that your CO alarm is working when it sounds an alarm. You and your loved ones and pets should immediately exit your home if your alarm goes off. Carbon monoxide exposure can be extremely dangerous and even lethal.

When should I replace my carbon monoxide detector?

Replace your carbon monoxide detector every 5 to 7 years or sooner if it shows an end-of-life warning, such as a consistent chirp or blinking light. Older detectors may not respond to dangerous CO levels. For added safety, upgrade to a smart CO detector with real-time alerts and easier monitoring.

Discover how Vivint can keep your home safe and secure

CO detectors should be a vital part of your home security system. Fortunately, Vivint offers peace of mind with our smart carbon monoxide and smoke combo detector.

The Vivint Smoke and CO Detector offers quick detection by using electrochemical sensors to identify carbon monoxide right away. It also integrates with the rest of your smart home to turn on the HVAC system to stimulate airflow, unlock doors for a quick exit, and can even contact emergency responders during an emergency.

Call us at 800.646.1469 for a free consultation today.