Carbon Monoxide Detectors: Ultimate Guide

Carbon monoxide (CO) is a common risk 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. Consequently, more than 400 people die of accidental carbon monoxide exposure each year, a higher fatality rate compared to any other kind of poisoning.

While the weather gets colder, you insulate your home for the winter and count on heating appliances to keep warm. This is when the danger of carbon monoxide exposure is highest. The good news is you can protect 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 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 something burned. Because of this, this gas is produced anytime a fuel source is burned, such as natural gas, propane, oil, charcoal, gasoline, woo, and more. Common causes of carbon monoxide in a house may be:

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

Do smoke detectors detect carbon monoxide?

No, smoke detectors do not detect carbon monoxide. Instead, they start an alarm when they recognize a certain concentration of smoke caused by a fire. Having functional smoke detectors lowers the risk of dying in a house fire by nearly 55 percent.

Smoke detectors come in two main modes—ionization detectors and photoelectric detectors. Ionization detection works best with fast-moving fires that produce large flames, while photoelectric models are more effective with smoldering, smoky fires. The newest smoke detectors include both types of alarms in one unit to maximize the chance of sensing a fire, despite how it burns.

Obviously, smoke detectors and CO alarms are similarly essential home safety devices. If you look up at the ceiling and notice an alarm of some kind, you might not realize whether it’s a smoke detector or a carbon monoxide alarm. The visual difference is based on the brand and model you prefer. Here are several 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 will also find a manufacture date. If the device is more than 10 years old, replace it at the earliest opportunity.
Plug-in devices that extract power with an outlet are almost always carbon monoxide sensors94. The device will be labeled saying as much.
Some alarms are really two-in-one, detecting both smoke and carbon monoxide with a different indicator light for each. Nevertheless, it can be difficult to tell with no label on the front, so 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 need depends on your home’s size, the number of stories and the number of bedrooms. Consider these guidelines to guarantee thorough coverage:

Add carbon monoxide detectors nearby sleeping areas: CO gas poisoning is most likely at night when furnaces must run constantly to keep your home heated. For that reason, every bedroom should have a carbon monoxide detector installed about 15 feet of the door. If a couple of bedroom doors are less than 30 feet apart, just one detector is enough.
Add detectors on each floor:
Concentrated carbon monoxide gas can become caught on a single floor of your home, so do your best to have at least one CO detector on all floors.
Install detectors within 10 feet of the internal garage door: Many people accidentally leave their cars on in the garage, leading to dangerous carbon monoxide gas, even when the large garage door is completely open. A CO sensor just inside the door—and in the room above the garage—alerts you of increased carbon monoxide levels within your home.
Put in detectors at the appropriate height: Carbon monoxide is a similar density as air, but it’s commonly carried upward in the hot air created by combustion appliances. Having detectors up against the ceiling is ideal to catch this rising air. Models that include digital readouts are best placed at eye level to make sure they're easy to read.
Put in detectors about 15 feet from combustion appliances: Certain fuel-burning machines produce a small, harmless amount of carbon monoxide at startup. This disperses quickly, but if a CO detector is nearby, it could give off false alarms.
Install detectors away from high heat and humidity: Carbon monoxide detectors have specified tolerances for heat and humidity. To reduce false alarms, try not to install them in bathrooms, in direct sunlight, around air vents, or close to heat-generating appliances.

How do I test/troubleshoot a carbon monoxide alarm?

Depending on the specific unit, the manufacturer will sometimes recommend monthly testing 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 is chirping, whichever happens first. Then, replace the CO detector entirely after 10 years or in line with the manufacturer’s instructions.

How to test your carbon monoxide alarm

All it takes is a minute to test your CO alarm. Check the instruction manual for directions unique to your unit, with the knowledge that testing follows this general routine:

Press and hold the Test button. It might take 5 to 20 seconds for the alarm to start.
Loud beeping means the detector is operating correctly.
Let go of the Test button and wait for two short beeps, a flash or both. If the device continues beeping when you release the button, press and hold it again for five seconds to quiet it.

Change the batteries if the unit won't work as expected for the test. If replacement batteries don’t change anything, replace the detector immediately.

How to reset your carbon monoxide alarm

You only need to reset your unit once the alarm goes off, after testing the device or after changing the batteries. Certain models automatically reset themselves in 10 minutes of these events, while others require a manual reset. The instruction manual will note which function is applicable.

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 hear a beep or observe a flash, start the reset again or replace the batteries. If nothing happens, troubleshoot your carbon monoxide alarm with assistance from the manufacturer, or replace the detector.

What do I do if a carbon monoxide alarm starts?

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

Do not ignore the alarm. You won't always be able to notice hazardous levels of carbon monoxide until it’s too late, so anticipate the alarm is functioning properly 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 a local fire department and explain that the carbon monoxide alarm has started.
Don't assume it’s safe to reenter your home when the alarm is no longer beeping. Opening windows and doors may help air it out, but the source could still be producing carbon monoxide.
When emergency responders come, they will search your home, measure carbon monoxide levels, try to find the source of the CO leak and establish if it’s safe to go back inside. Depending on the cause, you might need to request repair services to keep the problem from returning.

Seek Support from Fras-Air/General Service Experts

With the proper precautions, there’s no need to be afraid of carbon monoxide poisoning in your home. Besides installing CO alarms, it’s important to maintain your fuel-burning appliances, particularly as winter starts.

The team at Fras-Air/General Service Experts is ready to inspect, clean, diagnose and repair problems with furnaces, boilers, water heaters and other combustion appliances. We understand what signs indicate a potential carbon monoxide leak— including excessive soot, rusted flue pipes and a yellow, flickering burner flame—along with the necessary repairs to resolve them.

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