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Carbon monoxide, also abbreviated “CO”, is an odorless, colorless gas that comes from fossil fuel burning appliances — wood/pellet, natural gas, oil, propane, kerosene, coal, etc. It can be produced when burning any fuel. Carbon monoxide (CO) and carbon dioxide (CO2) are different. When you breath out, you are exhaling carbon dioxide (CO2). Incidentally, plants inhale carbon dioxide and exhale oxygen.

If your home has a fireplace, a furnace, a non-electric water heater, a non-electric stove/oven, a boiler, etc., the occupants are potentially in danger of carbon monoxide poisoning. Even if your home has none of these appliances but has an attached garage, there is still a potential carbon monoxide danger due to vehicle exhaust from the garage entering the home. Carbon monoxide exposure can injure or kill humans and animals. According to the Center for Disease Control (CDC), “Each year, more than 400 Americans die from unintentional CO poisoning not linked to fires, more than 20,000 visit the emergency room, and more than 4,000 are hospitalized.” According to the Environmental Protection Agency (EPA), CO is the most common cause of poisoning death in the U.S. CO poisoning is a real issue that everyone needs to be familiar with, and you should be able to recognize the symptoms.

Keep in mind that the detection of or testing for carbon monoxide (CO) is well outside the scope of a home inspection. The Standard of Practice of ASHI (the American Society of Home Inspectors), however, requires home inspectors to report on the presence or absence of installed carbon monoxide (CO) detectors and smoke detectors as part of a home inspection. If possible, I always try to determine the manufacture date for installed CO and smoke detectors; and I recommend older units be replaced.

Carbon monoxide poisoning mimics many of the same symptoms of the flu — dizziness, nausea, headache, fatigue, vomiting, confusion, etc. Since the warning signs can be very slow to be noticed, that is one of the dangers. A loss of consciousness indicates a severe exposure to or high concentration of CO. If you are sleeping and are poisoned by CO, you may never wake up. The complications of CO exposure can lead to brain damage, heart damage or death.

Carbon monoxide is a health hazard because once it’s inhaled, it combines with the oxygen carrying hemoglobin in the blood to form carboxyhemoglobin (COHb). This prevents needed oxygen from getting to your body’s organs, such as your brain. If many or all of your family members or pets are exhibiting flu-like symptoms, this is a clue that carbon monoxide poisoning may be the culprit. Get outside to fresh air immediately and call 911. The fire department is prepared to determine the cause/source of the issue. The cause of the CO problem needs to be repaired before anyone can safely go back into the home.

How Do I Protect My Family?

All homes should have at least one carbon monoxide (CO) detector installed. The 2015 International Residential Code (IRC) requires CO detectors to be installed outside sleeping areas (the code uses the term “sleeping areas” for bedrooms). This CO detector standard also existed in the 2009 IRC which the Commonwealth of PA was using until October 1, 2018. CO detectors, like smoke detectors, should never be installed near ceiling fans, near peaks on cathedral ceilings or near exterior doors or windows since these can prevent the detector from properly detecting dangerous exhaust gases in the air. CO detectors need to be replaced every 5-7 years, although some newer CO detectors being manufactured today have a 10-year life expectancy. This information would be clearly noted on the unit’s packaging. When these newer units reach 10 years of service life, they will beep to indicate that it is time to replace them. For older units, it is up to the homeowner to know when to replace them.

The sensor inside the CO detector, just like smoke detectors, has a relatively short life span. An old CO or smoke detector with brand new batteries likely won’t provide any useful protection if the sensor can no longer detect CO or smoke. If in doubt, replace your home’s CO and smoke detectors to be safe. Follow the instructions on your CO and smoke detector’s packaging regarding installation locations, testing procedures, when to replace, etc.

When most people think they are “testing” their CO and smoke detectors, they are actually only testing the unit’s power source. In other words, pressing the “test” button only confirms that the unit is powered, not that it will necessarily detect high levels of carbon monoxide or smoke in your home. You would need a source of CO near the detector to actually test it for its function. The same goes for smoke detectors . . . you would really only know if your smoke detector “works” by putting a source of smoke near its sensor.

Carbon monoxide exposure is generally measured in terms of parts per million (aka ppm). A CO exposure to 35 ppm over eight hours is the maximum exposure allowed by the Occupational Safety and Health Administration. Just two hours of exposure to CO at 200 ppm can lead to fatigue, headaches, nausea and dizziness. Two hours of CO exposure at 800 ppm can lead to unconsciousness or death. Over 1,000 ppm CO exposure for 20 minutes or less can lead to death. As you can see, it is critical that if you are exposed to carbon monoxide that you act quickly.

Carbon monoxide detectors won’t alarm immediately if detecting CO. Industry standards require that they must alarm within 60-240 minutes when a carbon monoxide concentration of 70 ppm is detected. They must alarm within 10-50 minutes when a concentration of 150 ppm is detected and within 4-15 minutes when a concentration of 400 ppm is detected.

The above photos show wall/ceiling mounted and plug-in style carbon monoxide (CO) detectors.

Part II of Carbon Monoxide: The Silent Killer will be posted soon.

Matthew Steger, ACI, WIN Home Inspection 

Facts, opinions and information expressed in the Closing Comments Blog represent the work of the author and are believed to be accurate, but are not guaranteed. The Lancaster County Association of Realtors® is not liable for any potential errors, omissions or outdated information. If errors are noted within a post, please notify the Association. Posts represent the author’s opinion and are not necessarily the opinion of the Association.

Lancaster County Association of Realtors®

Lancaster County Association of Realtors®