Carbon Monoxide Detectors: Ultimate Guide

Carbon monoxide (CO) is a common risk found in the home. Known as the “silent killer,” CO gas is colorless, odorless, tasteless and non-irritating, yet it can result in unconsciousness, brain damage or death. Because of this, more than 400 people die as a result of carbon monoxide influence each year, a larger fatality rate compared to other types of poisoning.

When the weather cools off, you insulate your home for the winter and count on heating appliances to remain warm. This is when the threat of carbon monoxide exposure is highest. Fortunately you can safeguard your family from a gas leak in a variety of ways. One of the most efficient methods is to add CO detectors in your home. Check out this guide to help you understand where carbon monoxide is produced and how to take full advantage of your CO alarms.

What produces carbon monoxide in a house?

Carbon monoxide is a byproduct of something burned. Therefore, this gas is produced whenever a fuel source is ignited, like natural gas, propane, oil, charcoal, gasoline, woo, and more. Prevalent causes of carbon monoxide in a house include:

  • Clogged clothes dryer vent
  • Malfunctioning water heater
  • Furnace or boiler with a damaged heat exchanger
  • Closed fireplace flue while a fire is lit
  • Improperly vented gas or wood stove
  • Vehicle running in the garage
  • Portable generator, grill, power tool or lawn equipment operating in the garage

Do smoke detectors detect carbon monoxide?

No, smoke detectors do not detect carbon monoxide. In fact, they start an alarm when they recognize a certain concentration of smoke produced by a fire. Having functional smoke detectors decreases the risk of dying in a house fire by around 55 percent.

Smoke detectors come in two primary types—ionization detectors and photoelectric detectors. Ionization detection is ideal with fast-growing fires that produce large flames, while photoelectric detectors are more effective with smoldering, smoky fires. Some newer smoke detectors include both forms of alarms in one unit to increase the chance of recognizing a fire, regardless of how it burns.

Obviously, smoke detectors and CO alarms are both essential home safety devices. If you inspect the ceiling and find an alarm of some kind, you may not know whether it’s a smoke detector or a carbon monoxide alarm. The visual difference is determined by the brand and model you have. Here are a few factors to remember:

  • Most devices are visibly labeled. If not, try to find a brand and model number on the back of the detector and look it up online. You can also find a manufacture date. If the device is more than 10 years old, replace it at the earliest opportunity.
  • Plug-in devices that use power from an outlet are typically carbon monoxide sensors be labeled so.
  • Some alarms are really two-in-one, sensing both smoke and carbon monoxide with an indicator light for each. Nevertheless, it can be difficult to tell with no label on the front, so double checking the manufacturing details on the back is your best bet.

How many carbon monoxide detectors do I need in my home?

The number of CO alarms you need is determined by your home’s size, how many floors it has and the number of bedrooms. Use these guidelines to guarantee complete coverage:

  • Add carbon monoxide detectors nearby bedrooms: CO gas leaks are most common at night when furnaces are running frequently to keep your home comfortable. As a result, each bedroom should have a carbon monoxide detector installed about 15 feet of the door. If two bedroom doors are less than 30 feet apart, one detector is sufficient.
  • Install detectors on each floor: Dangerous carbon monoxide buildup can become caught on a single floor of your home, so try to have at least one CO detector on all floors.
  • Put in detectors within 10 feet of an attached garage door: Many people unsafely leave their cars on in the garage, leading to dangerous carbon monoxide buildup, even if the large garage door is fully open. A CO sensor just inside the door—and in the room up above the garage—alerts you of increased carbon monoxide levels within your home.
  • Have detectors at the appropriate height: Carbon monoxide features a weight similar to air, but it’s commonly pushed up by the hot air produced by combustion appliances. Having detectors near the ceiling is ideal to catch this rising air. Models that come with digital readouts are best placed at eye level to keep them easy to read.
  • Install detectors around 15 feet from combustion appliances: Some fuel-burning machines produce a small, non-toxic amount of carbon monoxide as they first start running. This dissipates quickly, but in situations where a CO detector is nearby, it may lead to false alarms.
  • Have detectors away from excess heat and humidity: Carbon monoxide detectors have certain tolerances for heat and humidity. To minimize false alarms, avoid installing them in bathrooms, in strong sunlight, next to air vents, or close to heat-generating appliances.

How do I test/troubleshoot a carbon monoxide detector?

Depending on the model, the manufacturer may recommend monthly tests and resetting to sustain proper functionality. Also, change out the batteries in battery-powered units twice a year. For hardwired units, replace the backup battery once a year or when the alarm begins chirping, whichever starts first. Then, replace the CO detector entirely after 10 years or in line with the manufacturer’s guidelines.

How to test your carbon monoxide alarm

You only need a minute to test your CO sensor. Check the instruction manual for directions individual to your unit, knowing that testing follows this general procedure:

  • Press and hold the Test button. It might take 5 to 20 seconds for the alarm to begin.
  • Loud beeping signifies the detector is operating correctly.
  • Release the Test button and wait for two short beeps, a flash or both. If the device keeps beeping when you release the button, press and hold it again for five seconds to stop it.

Swap out the batteries if the unit fails to perform as expected for the test. If replacement batteries don’t help, replace the detector entirely.

How to reset your carbon monoxide alarm

You’re only required to reset your unit after the alarm goes off, after a test or after swapping the batteries. Certain models automatically reset themselves in under 10 minutes of these events, while other alarms need a manual reset. The instruction manual should note which function applies.

Follow these steps to reset your CO detector manually:

  • Press and hold the Reset button for 5 to 10 seconds.
  • Release the button and listen for a beep, a flash or both.

If you don’t get a beep or observe a flash, start the reset again or replace the batteries. If it’s still not working, troubleshoot your carbon monoxide alarm with support from the manufacturer, or replace the detector.

What do I do if a carbon monoxide alarm goes off?

Listen to these steps to take care of your home and family:

  • Do not ignore the alarm. You won’t always be able to detect dangerous levels of carbon monoxide until it’s too late, so expect the alarm is functioning properly when it is triggered.
  • Evacuate all people and pets immediately. If possible, open windows and doors on your way out to attempt to thin out the concentration of CO gas.
  • Call 911 or your local fire department and explain that the carbon monoxide alarm has started.
  • It’s wrong to think it’s safe to reenter your home when the alarm is no longer beeping. Opening windows and doors might help air it out, but the source may still be creating carbon monoxide.
  • When emergency responders show up, they will go into your home, evaluate carbon monoxide levels, try to find the source of the CO leak and determine if it’s safe to return. Depending on the cause, you will sometimes need to request repair services to stop the problem from returning.

Find Support from Norrell Service Experts

With the right precautions, there’s no need to worry about carbon monoxide poisoning in your home. Along with installing CO alarms, it’s worthwhile to maintain your fuel-burning appliances, namely as winter starts.

The team at Norrell Service Experts is qualified to inspect, clean, diagnose and repair malfunctions with furnaces, boilers, water heaters and other combustion appliances. We recognize which signs indicate a possible carbon monoxide leak— like excessive soot, rusted flue pipes and a yellow, flickering burner flame—along with the necessary repairs to prevent them.

Do you still have questions or concerns about CO exposure? Is it time to schedule annual heating services? Contact Norrell Service Experts for more information.

Savings For You

See All Offers Here >


  • Written 100% Satisfaction Guarantee

© 2024 Service Experts, Service Experts Heating & Air Conditioning, and the Service Experts logo and design are registered trademarks of Service Experts LLC and used under license by SE Canada Inc. All Rights Reserved. *Not applicable to the Advantage Program. See your signed Advantage Program Agreement for full details and exclusions. 100% Satisfaction Guarantee is subject to certain restrictions and limitations as set forth in the applicable Terms and Conditions.

Chat with a Service Experts Professional