Carbon Monoxide Detectors: Ultimate Guide

Carbon monoxide (CO) is one of the most hazardous gases found in the home. Dubbed the “silent killer,” CO gas is colorless, odorless, tasteless and non-irritating, yet it can cause unconsciousness, brain damage or death. As a result, more than 400 people die of accidental carbon monoxide exposure each year, a higher fatality rate than any other type of poisoning. 

As the weather cools off, you close up your home for the winter and rely on heating appliances to stay warm. This is when the risk of carbon monoxide poisoning is highest. The good news is you can protect your family from carbon monoxide in several ways. One of the most effective methods is to install CO detectors in your home. Use this guide to help you understand where carbon monoxide comes from and how to make the most of your CO alarms. 

What causes carbon monoxide in a house? 

Carbon monoxide is a byproduct of incomplete combustion. As a result, this gas is produced whenever a fuel source burns, including natural gas, propane, oil, charcoal, gasoline, woo, and more. Common causes of carbon monoxide in a house include: 

• Clogged clothes dryer vent 

• Malfunctioning water heater 
• Furnace or boiler with a cracked heat exchanger
• Closed fireplace flue while a fire is lit 
• Improperly vented gas or wood stove 
• Vehicle idling 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. Instead, they sound an alarm when they sense a certain level of smoke caused by a fire. Having functional smoke detectors reduces the risk of dying in a house fire by nearly 55 percent. 

Smoke detectors come in two primary forms—ionization detectors and photoelectric detectors. Ionization detection works best with fast-moving fires that produce large flames, while photoelectric detection is more effective with smoldering, smoky fires. Some newer smoke detectors come with both types of alarms in a single unit to increase the chance of sensing a fire, no matter how it burns. 

Clearly, smoke detectors and CO alarms are equally important home safety devices. If you look up at the ceiling and see an alarm of some kind, you may not know whether it’s a smoke detector or a carbon monoxide alarm. The visual difference depends on the brand and model you have. Here are some factors to keep in mind: 

• Some devices are clearly labeled. If not, check for a brand and model number on the back of the detector and look it up online. You should also find a manufacture date. If the device is more than 10 years old, replace it as soon as possible. 
• Plug-in devices that draw power from an outlet are almost always carbon monoxide detectors be labeled as such. 
• Some alarms are two-in-one, detecting both smoke and carbon monoxide with a separate indicator light for each. Still, it can be hard to tell without a label on the front, so 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 depends on your home’s size, number of floors and bedroom arrangement. Follow these guidelines to ensure thorough coverage: 

• Install carbon monoxide detectors near sleeping areas: CO gas leaks are most common at night when furnaces must run frequently to keep your home warm. Therefore, all bedrooms should have a carbon monoxide detector installed within 15 feet of the door. If two bedroom doors are less than 30 feet apart, one detector is sufficient. 
• Install detectors on every floor: 
  Dangerous carbon monoxide buildup can become trapped on a single floor of your home, so make sure you have at least one CO detector on every level. 
• Install detectors within 10 feet of the internal garage door: Many people unsafely leave their cars idling in the garage, leading to dangerous carbon monoxide buildup, even when the large garage door is wide open. A CO detector immediately inside the door—and in the room above the garage—alerts you of elevated carbon monoxide levels entering your home. 
• Install detectors at the proper height: Carbon monoxide weighs about the same as air, but it’s often carried upward in the hot air produced by combustion appliances. Installing detectors near the ceiling is best to catch this rising air. Models with digital readouts are best placed at eye level to make them easier to read. 
• Install detectors at least 15 feet from combustion appliances: Some fuel-burning machines give off a tiny, harmless amount of carbon monoxide at startup. This dissipates quickly, but if a CO detector is positioned too close, it could give off false alarms. 

• Install detectors away from high heat and humidity: Carbon monoxide detectors have specific tolerances for heat and humidity. To reduce false alarms, avoid installing them in bathrooms, in direct sunlight, near air vents, or close to heat-generating appliances. 

How do I test/troubleshoot a carbon monoxide alarm? 

Depending on the model, the manufacturer may recommend monthly testing and resetting to ensure proper functionality. Also, replace the batteries in battery-powered units every six months. For hardwired units, replace the backup battery once a year or when the alarm starts chirping, whichever comes first. Then, replace the CO detector entirely every 10 years or according to the manufacturer’s guidelines. 

How to test your carbon monoxide alarm 

It only takes a minute to test your CO detector. Check the instruction manual for directions specific to your unit, knowing that testing follows this general procedure: 

• Press and hold the Test button. It may take 5 to 20 seconds for the alarm to go off. 
• Loud beeping indicates the detector is working correctly. 
• Release the Test button and wait for two quick beeps, a flash or both. If the device continues beeping when you release the button, press and hold it again for five seconds to silence it. 

Change the batteries if the unit fails to perform as expected during the test. If replacement batteries don’t make a difference, replace the detector immediately. 

How to reset your carbon monoxide alarm 

You only need to reset your unit when the alarm goes off, after testing the device or after replacing the batteries. Some models automatically reset themselves within 10 minutes of these events, while others require a manual reset. The instruction manual will 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 wait for a beep, a flash or both. 

If you don’t hear a beep or see 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 do I do if a carbon monoxide alarm goes off? 

Follow these steps to protect your home and family: 

• Do not ignore the alarm. You may not be able to detect unsafe levels of carbon monoxide until it’s too late, so assume the alarm is working correctly when it goes off. 
• Evacuate all people and pets as quickly as possible. If you can, open windows and doors on your way out to help dilute the concentration of CO gas. 
• Call 911 or your local fire department and report that the carbon monoxide alarm has gone off. 

• Do not assume it’s safe to reenter your home when the alarm stops beeping. Opening windows and doors may help air it out, but the source could still be producing carbon monoxide. 
• When emergency responders arrive, they will enter your home, measure carbon monoxide levels, check for the source of the CO leak and determine if it’s safe to go back inside. Depending on the cause, you may need to arrange repair services to prevent the problem from recurring. 

Seek Support from Service Experts Heating, Air Conditioning & Plumbing 

With the proper precautions, there’s no need to fear carbon monoxide exposure in your home. In addition to installing CO alarms, it’s important to maintain your fuel-burning appliances, especially as winter gets underway. 

The team at Service Experts Heating, Air Conditioning & Plumbing is qualified to inspect, clean, diagnose and repair problems with furnaces, boilers, water heaters and other combustion appliances. We know what signs indicate a possible carbon monoxide leak— such as 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 Service Experts Heating, Air Conditioning & Plumbing for more information.