Carbon monoxide (CO) is an odorless, colorless gas that can be deadly if inhaled. Knowing the CO levels in your home is important to help prevent carbon monoxide poisoning. Here are some key things to know about testing for carbon monoxide in your home:
What is carbon monoxide and why is it dangerous?
Carbon monoxide is a gas that is produced any time a fossil fuel such as natural gas, propane, gasoline, oil, or wood is burned. Appliances like furnaces, water heaters, fireplaces, generators, and stoves all burn fuel and produce CO as a byproduct of incomplete combustion.
CO is dangerous because it bonds to the hemoglobin in your blood about 200-300 times more readily than oxygen. When you breathe in CO, it replaces the oxygen in your blood, depriving your heart, brain, and other organs of oxygen. This can lead to flu-like symptoms, confusion, unconsciousness, and even death at high concentrations. Hundreds of people in the U.S. die from accidental CO poisoning every year.
What are the symptoms of carbon monoxide poisoning?
At lower concentrations, carbon monoxide poisoning can cause symptoms like:
- Headache
- Dizziness
- Nausea
- Fatigue
- Shortness of breath
- Confusion
Higher concentrations of CO can cause more severe symptoms like:
- Impaired vision and coordination
- Unconsciousness
- Brain damage
- Death
The effects depend on the concentration of CO and length of exposure. Infants, pregnant women, the elderly, and those with chronic heart disease are most susceptible.
How can I test for carbon monoxide in my home?
There are a few options for testing carbon monoxide levels in your home:
Carbon monoxide detectors
CO detectors work similarly to smoke detectors – they constantly monitor the air for CO and sound an alarm if levels rise above a certain threshold. The Consumer Product Safety Commission recommends installing battery-powered or plug-in CO detectors with an Underwriters Laboratories (UL) mark in your home.
Ideally, you should have a CO detector on every level of the home and near every sleeping area. Make sure to replace detectors according to the manufacturer’s instructions, usually every 5-7 years. Test detectors monthly by pressing the test button.
Spot detectors
Handheld spot detectors can measure CO levels at a specific moment in time. They are useful for getting instant readings if your alarm goes off or you suspect a CO leak. Spot detectors are not meant to be used as standalone carbon monoxide monitors. Look for ones approved by UL or the Occupational Safety and Health Administration (OSHA).
Smart carbon monoxide detectors
Newer “smart” CO detectors can connect to your smartphone via WiFi and send real-time alerts and CO readings straight to an app. This allows you to monitor levels remotely. Smart detectors also log data, so you can review CO patterns and high points.
What CO levels are dangerous?
Here are carbon monoxide guidelines from the Environmental Protection Agency (EPA) and Consumer Product Safety Commission (CPSC):
| CO Concentration (parts per million) | Health Effects |
|---|---|
| 35 ppm | Background outdoor level |
| 70 ppm | Max acceptable short-term indoor exposure (ASHRAE standard) |
| 150 ppm | OSHA 8-hour permissible exposure limit |
| 200 ppm | Slight headache, fatigue, dizziness, nausea after 2-3 hours |
| 400 ppm | Serious headache, serious symptoms after 1-2 hours |
| 800 ppm | Dizziness, nausea, convulsions within 45 minutes. Unconsciousness after 2 hours. Death within 2-3 hours. |
| 1600 ppm | Headache, dizziness, nausea within 20 minutes. Death within 1 hour. |
| 12800 ppm | Death within 1-3 minutes |
As you can see, fairly low concentrations like 200-400 ppm can cause moderate CO poisoning symptoms over time. Levels about 800 ppm and higher can be fatal over shorter periods.
How to find CO leaks in your home
If your CO detector frequently sounds or you suspect a leak, take these steps:
- Evacuate your home and call 911 if CO levels are dangerously high.
- Call your gas company or a professional HVAC technician to inspect for leaks and malfunctioning appliances.
- Check for leaks around furnaces, water heaters, stoves, fireplaces, and any other combustion appliances. Look for visible rust, stains, moisture, or loose connections.
- Check the color of the flames – yellow or orange flames can indicate an issue.
- Look at exhaust vent pipes to make sure they are intact, properly connected, and venting outside.
- Inspect chimneys and flues for blockages or debris issues.
- Test the garage if you leave a car running – CO from the vehicle can migrate indoors.
- Consider investing in a carbon monoxide monitor system that can pinpoint sources of CO.
Never ignore your CO detector’s warnings or the physical symptoms of carbon monoxide poisoning. Take action quickly, as CO can be life-threatening.
How to prevent carbon monoxide poisoning
Here are some key tips for avoiding CO issues in your home:
- Install CO detectors on every level per CPSC guidelines.
- Check chimneys and vents annually before first use for blockages.
- Only use generators outdoors at least 20 feet from the home.
- Never idle a car in a garage, even with the garage door open.
- Don’t use gas stoves or ovens for heat.
- Have furnaces, flues, and chimneys inspected yearly by an HVAC contractor.
- Replace furnace filters regularly.
- Make sure appliances are in good working order and serviced when needed.
- Never burn charcoal indoors or in an unventilated space.
Being vigilant, having working CO detectors, and properly maintaining combustion appliances are the best ways to protect your home from dangerous carbon monoxide exposure.
What should I do if my CO detector goes off?
If your CO alarm activates, follow these steps:
- Evacuate your home immediately and call 911. Tell operators you have a CO emergency.
- Do a head count to check that all people and pets are accounted for.
- Do not re-enter the home until emergency responders say it is safe.
- Call your gas company once outside and have them inspect for leaks.
- If the source is not found, have HVAC appliances inspected by a professional before using them again.
- Consider investing in a CO monitoring system to help track down sources.
- If alarm activations are very frequent, relocate the detector as CO may be seeping in from the garage.
Never ignore a CO alarm – high levels can be fatal within minutes. Evacuate right away and let professionals assess the situation.
Conclusion
Testing for and preventing carbon monoxide exposure is incredibly important for home safety. Installing UL-listed CO detectors on every level and near bedrooms provides monitoring of CO levels. If an alarm sounds, evacuate immediately and call 911 – carbon monoxide is deadly at high concentrations. Prevent CO issues by properly maintaining and servicing combustion appliances, installing detectors, and addressing leaks right away. Being proactive about carbon monoxide testing and prevention can help keep your family safe.