Carbon Monoxide Detectors: Ultimate Guide

Carbon monoxide (CO) is a potentially hazardous gas found in the home. Nicknamed the “silent killer,” CO gas is colorless, odorless, tasteless and non-irritating, however it can cause unconsciousness, brain damage or death. Consequently, more than 400 people suffer fatal carbon monoxide poisoning each year, a larger fatality rate versus other types of poisoning. 

As the weather cools off, you seal your home for the winter and rely on heating appliances to stay warm. This is where the threat of carbon monoxide poisoning is highest. Thankfully you can safeguard your family from carbon monoxide in a variety of ways. One of the most successful methods is to install CO detectors around your home. Use this guide to better understand where carbon monoxide can appear from and how to take full advantage of your CO detectors. 

What generates carbon monoxide in a house? 

Carbon monoxide is a byproduct of incomplete combustion. Therefore, this gas is generated whenever a fuel source burns, such as natural gas, propane, oil, charcoal, gasoline, woo, and more. Frequent causes of carbon monoxide in a house include: 

  • Clogged clothes dryer vent 
  • Broken down water heater 
  • Furnace or boiler with a broken 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 sense carbon monoxide? 

No, smoke detectors do not detect carbon monoxide. Alternatively, they sound an alarm when they detect a certain level of smoke generated by a fire. Installing functional smoke detectors reduces the risk of dying in a house fire by about 55 percent

Smoke detectors are available in two primary forms—ionization detectors and photoelectric detectors. Ionization detection functions well with fast-moving fires that generate large flames, while photoelectric detection is more suited for smoldering, smoky fires. A few smoke detectors include both kinds of alarms in a single unit to boost the chance of recognizing a fire, regardless of how it burns. 

Obviously, smoke detectors and CO alarms are equally beneficial home safety devices. If you look up at the ceiling and notice an alarm of some kind, you won’t always recognize whether it’s a smoke detector or a carbon monoxide alarm. The visual discrepancy is based on the brand and model you want. Here are some factors to remember: 

  • Some devices are clearly labeled. If not, check for a brand and model number on the back of the detector and find it online. You will also find a manufacture date. If the device is more than a decade old, replace it at the earliest opportunity. 
  • Plug-in devices that draw power from an outlet are generally carbon monoxide will be labeled so. 
  • Some alarms are really two-in-one, offering protection against both smoke and carbon monoxide with an indicator light for each. Nevertheless, it can be tough to tell if there’s no label on the front, so double checking the manufacturing details on the back is worthwhile. 

How many carbon monoxide detectors will I want in my home? 

The number of CO alarms you require is dependent on your home’s size, how many floors it has and bedroom arrangement. Follow these guidelines to guarantee complete coverage: 

  • Add carbon monoxide detectors nearby bedrooms: CO gas exposure is most common at night when furnaces are running frequently to keep your home comfortable. For that reason, every bedroom should have a carbon monoxide alarm installed within 15 feet of the door. If a couple of bedroom doors are less than 30 feet apart, one detector is adequate. 
  • Add detectors on all floors: 
    Dangerous carbon monoxide buildup can become stuck on a single floor of your home, so make sure you have at least one CO detector on all floors. 
  • Have detectors within 10 feet of the internal garage door: A surprising number of people unsafely leave their cars on in the garage, leading to dangerous carbon monoxide gas, even when the large garage door is wide open. A CO alarm immediately inside the door—and in the room up above the garage—alerts you of elevated carbon monoxide levels within your home. 
  • Install detectors at the correct height: Carbon monoxide weighs about the same as air, but it’s commonly carried upward in the hot air released by combustion appliances. Having detectors close to the ceiling is ideal to catch this rising air. Models that come with digital readouts are best installed at eye level to keep them easy to read. 
  • Add detectors around 15 feet from combustion appliances: A few fuel-burning machines give off a small, non-toxic amount of carbon monoxide as they first start running. This breaks up quickly, but when a CO detector is positioned too close, it may give off false alarms. 
  • Put in detectors away from high heat and humidity: Carbon monoxide detectors have specific tolerances for heat and humidity. To reduce false alarms, don’t install them in bathrooms, in direct sunlight, near air vents, or close to heat-generating appliances. 

How do I test/troubleshoot a carbon monoxide sensor? 

Depending on the model, the manufacturer may encourage testing once a month and resetting to maintain proper functionality. Also, change out the batteries in battery-powered units every six months. For hardwired units, replace the backup battery annually or when the alarm begins chirping, whichever comes first. Then, replace the CO detector completely every 10 years or according to the manufacturer’s recommendations. 

How to test your carbon monoxide alarm 

You only need a minute to test your CO sensor. Read the instruction manual for directions specific to your unit, understanding that testing follows this general process: 

  • Press and hold the Test button. It will sometimes need 5 to 20 seconds for the alarm to begin. 
  • Loud beeping means the detector is working correctly. 
  • Release the Test button and wait for two short beeps, a flash or both. If the device goes on beeping when you let go of the button, press and hold it again for five seconds to silence it. 

Replace the batteries if the unit isn’t performing as expected during the test. If replacement batteries don’t change anything, replace the detector entirely. 

How to reset your carbon monoxide alarm 

You only have to reset your unit once the alarm goes off, after a test or after swapping the batteries. Certain models automatically reset themselves in 10 minutes of these events, while other models require a manual reset. The instruction manual can note which function applies. 

Use these steps to reset your CO detector manually: 

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

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

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

Use these steps to safeguard your home and family: 

  • Do not dismiss the alarm. You won’t always be able to notice hazardous levels of carbon monoxide until it’s too late, so assume the alarm is functioning correctly when it starts. 
  • Evacuate all people and pets as soon as possible. If you’re able to, open windows and doors on your way out to help thin out the concentration of CO gas. 
  • Call 911 or your local fire department and report 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 can help air it out, but the root cause may still be generating carbon monoxide. 
  • When emergency responders show up, they will go into your home, evaluate carbon monoxide levels, check for the source of the CO leak and figure out if it’s safe to come back inside. Depending on the cause, you may need to schedule repair services to keep the problem from returning. 

Find Support from Service Experts Heating, Air Conditioning & Plumbing 

With the proper precautions, there’s no need to worry about carbon monoxide inhalation in your home. Besides installing CO alarms, it’s worthwhile to maintain your fuel-burning appliances, particularly as winter arrives. 

The team at Service Experts Heating, Air Conditioning & Plumbing is happy to inspect, clean, diagnose and repair issues with furnaces, boilers, water heaters and other combustion appliances. We know what signs could mean a possible carbon monoxide leak— like excess soot, rusted flue pipes and a yellow, flickering burner flame—along with the necessary repairs to avoid them. 

Do you still have questions or concerns about CO exposure? Is it time to schedule annual heating services? Contact Service Experts Heating, Air Conditioning & Plumbing for more information. 

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