Carbon Monoxide Detectors: Ultimate Guide

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

When the weather cools off, you close up your home for the winter and count on heating appliances to stay warm. This is where the danger of carbon monoxide poisoning is highest. Fortunately you can safeguard your family from carbon monoxide in different ways. One of the most efficient methods is to add CO detectors throughout your home. Use this guide to help you understand where carbon monoxide comes from and how to make the most of your CO detectors.

What causes carbon monoxide in a house?

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

Overloaded clothes dryer vent
Broken down water heater
Furnace or boiler with a broken heat exchanger
Closed fireplace flue while a fire is lit
Poorly vented gas or wood stove
Vehicle idling in the garage
Portable generator, grill, power tool or lawn equipment being used in the garage

Do smoke detectors sense carbon monoxide?

No, smoke detectors do not detect carbon monoxide. In fact, they begin 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 nearly 55 percent.

Smoke detectors come in two primary types—ionization detectors and photoelectric detectors. Ionization detection works best with fast-moving fires that generate large flames, while photoelectric detection is more effective with smoldering, smoky fires. Some newer smoke detectors include both types of alarms in a single unit to maximize the chance of recognizing a fire, despite how it burns.

Unmistakably, 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 is determined by the brand and model you prefer. Here are some factors to keep in mind:

Most devices are visibly labeled. If not, try to find a brand and model number on the back of the detector and find it online. You can also find a manufacture date. If the device is more than a decade old, replace it at the earliest opportunity.
Plug-in devices that use power with an outlet are typically carbon monoxide detectors94. The device will be labeled saying as much.
Some alarms will be two-in-one, detecting both smoke and carbon monoxide with a different indicator light for each. Still, it can be tough 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 should I install in my home?

The number of CO alarms you need is determined by your home’s size, number of floors and the number of bedrooms. Consider these guidelines to guarantee total coverage:

Install carbon monoxide detectors near sleeping areas: CO gas poisoning is most common at night when furnaces must run more often to keep your home heated. Therefore, each bedroom should have a carbon monoxide detector installed about 15 feet of the door. If multiple bedroom doors are less than 30 feet apart, just one detector is enough.
Put in detectors on each floor:
Concentrated carbon monoxide buildup can become caught on a single floor of your home, so make sure you have at least one CO detector on every level.
Put in detectors within 10 feet of your internal garage door: A lot of people accidentally leave their cars on in the garage, producing dangerous carbon monoxide buildup, even if the large garage door is wide open. A CO sensor immediately inside the door—and in the room over the garage—alerts you of increased carbon monoxide levels inside your home.
Have detectors at the correct height: Carbon monoxide weighs about the same as air, but it’s frequently carried along with the hot air produced by combustion appliances. Having detectors up against the ceiling is ideal to catch this rising air. Models with digital readouts are best placed at eye level to keep them easy to read.
Install detectors at least 15 feet from combustion appliances: Certain fuel-burning machines give off a tiny, non-toxic amount of carbon monoxide as they first start running. This dissipates quickly, but if a CO detector is nearby, it may trigger false alarms.
Put in detectors away from extreme heat and humidity: Carbon monoxide detectors have certain tolerances for heat and humidity. To reduce false alarms, try not to install them in bathrooms, in strong sunlight, next to air vents, or close to heat-generating appliances.

How do I test/troubleshoot a carbon monoxide sensor?

Depending on the specific unit, the manufacturer might suggest monthly tests and resetting to ensure proper functionality. Also, replace the batteries in battery-powered units after 6 months. For hardwired units, replace the backup battery once a year or when the alarm starts chirping, whichever happens first. Then, replace the CO detector entirely every 10 years or in line with the manufacturer’s recommendations.

How to test your carbon monoxide alarm

All it takes is a minute to test your CO sensor. Review the instruction manual for directions specific to your unit, with the knowledge that testing practices this general routine:

Press and hold the Test button. It may take 5 to 20 seconds for the alarm to start.
Loud beeping indicates the detector is working correctly.
Let go of the Test button and wait for two quick 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 won't work as expected for the test. If replacement batteries don’t make a difference, replace the detector immediately.

How to reset your carbon monoxide alarm

You're only required to reset your unit once the alarm goes off, after a test or after changing the batteries. Some models automatically reset themselves within 10 minutes of these events, while others need a manual reset. The instruction manual will note which function you should use.

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 notice a beep or see a flash, start the reset again or replace the batteries. If nothing happens, 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 safeguard your home and family:

Do not dismiss the alarm. You might not be able to detect unsafe levels of carbon monoxide until it’s too late, so expect the alarm is working correctly when it goes off.
Evacuate all people and pets as quickly 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 a local fire department and inform them that the carbon monoxide alarm has triggered.
It's wrong to think it’s safe to reenter your home when the alarm stops running. Opening windows and doors may help air it out, but the source might still be producing carbon monoxide.
When emergency responders come, they will enter your home, assess carbon monoxide levels, check for the source of the CO leak and figure out if it’s safe to return. Depending on the cause, you might need to arrange repair services to keep the problem from reappearing.

Find Support from Service Experts Heating & Air Conditioning

With the appropriate precautions, there’s no need to fear carbon monoxide inhalation in your home. In addition to installing CO alarms, it’s important to maintain your fuel-burning appliances, particularly as winter starts.

The team at Service Experts Heating & Air Conditioning is happy to inspect, clean, diagnose and repair issues with furnaces, boilers, water heaters and other combustion appliances. We recognize which signs suggest a possible carbon monoxide leak— like increased 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 for more information.