Carbon Monoxide Detectors

Known as the ‘silent killer’, carbon monoxide (CO) is a colorless, odorless, tasteless, and toxic gas produced as a by-product of combustion. Any fuel-burning appliance, vehicle, tool, or other device has the potential to produce dangerous levels of CO gas. Examples of CO emitters around the home include: automobiles; fireplaces, space heaters; fuel-fired furnaces, gas dryers, stoves, and water heaters. Carbon monoxide inhibits the blood’s ability to carry oxygen, eventually depriving and stopping the brain, heart, and other organs.

According to the Consumer Product Safety Commission, the home heating system is the most common cause. The first symptoms of carbon monoxide poisoning are often mistaken for common illnesses like the flu. Victims of low-level carbon monoxide poisoning often experience mild headaches, shortage of breath, nausea, drowsiness, and dizzy spells. At higher levels, carbon monoxide causes severe headaches, mental confusion, impairment of vision or hearing, vomiting, fatigue, loss of consciousness, and coma. Severe carbon monoxide poisoning can cause an irregular heartbeat, amnesia, brain damage, coma, and eventually death. High-risk groups include fetuses, children, the elderly, and those with heart and lung disorders. When inhaled, carbon monoxide combines with hemoglobin in the red blood cells to form substances that work to decrease oxygen levels and eventually asphyxiate the victim. Many people are unaware that they are being poisoned until it is too late.


There are hundreds of different types and brands of carbon monoxide detectors on the market today. They can most easily be characterized by whether they operate on household current or batteries. The most important component of either is the type of sensor they house. Hard-wired carbon monoxide detectors using household current typically employ some type of solid-state sensor which purges itself and resamples for carbon monoxide on a periodic basis. These detectors give a continuous display of carbon monoxide levels and require no maintenance during the life of the product. They generally have a life expectancy of five to ten years.

Detectors powered by batteries typically use a passive sensor that reacts to the prolonged exposure to carbon monoxide gas. Prices range from around $30.00 for a battery-operated model up to $100.00 for more elaborate models that may detect both smoke and carbon monoxide. Battery-operated models are only as reliable as the battery and, like smoke detectors, should be tested regularly and batteries should be replaced annually. The cheaper detectors generally carry a one year warranty and provide minimal protection. More effective detectors with 9-volt batteries have a life expectancy of about 6 years and are often guaranteed for that length of time. Some carbon monoxide detectors sound an alarm similar to a smoke detector when carbon monoxide levels become dangerous. This is often accompanied by a flashing light.


Carbon monoxide detectors

Carbon monoxide detectors are mandatory in new homes and must be hard-wired into the electrical system. According to Building Code, they must be installed inside of each bedroom, in the garage, and at the top of each staircase. In older homes where hard-wiring may be problematic, battery-operated or plug-in models are recommended in the same areas. For maximum security, carbon monoxide detectors should be installed in each room where there is a source of combustion such as locations of fireplaces, gas appliances, etc. Ceiling mounted detectors should be installed in the center of the room. Wall-mounted detectors should be installed at least three feet from the door. Avoid installing carbon monoxide detectors near open windows or doors or in damp or very humid areas such as bathrooms as these locations can delay the alarm. Do not install them behind furniture or drapes or in closets or areas that block airflow to the alarm.


  • Install the carbon monoxide detector according to the manufacturer’s instructions. This will ensure that it works. As with all detectors, test your carbon monoxide detector regularly according to the manual. Also, replace your carbon detector according to the manual as they tend to wear out in time.
  • Have furnaces, hot water heaters, vents, chimneys, and space heaters inspected annually by a qualified service technician.
  • Have your vent pipe and chimney flues inspected and cleaned once a year by a certified professional. Birds’ nests, twigs, and old mortar in chimneys can block proper ventilation and lead to a buildup of carbon monoxide gas in the home.
  • Make regular visual inspections of all fuel-burning equipment including gas water heaters, space heaters, gas ranges, and gas dryers. The colour of the pilot flame should be blue. A yellow flame means the fuel is not burning completely and hazardous levels of carbon monoxide may be present.
  • Investigate appliances that emit unusual odours or sounds.
  • Never heat with a gas range or oven.
  • Never leave a car running in a garage.
  • Never use an unvented gas or kerosene space heater in a room where a person is sleeping.
  • Be aware of the symptoms of carbon monoxide and note if others (including pets) demonstrate them. Also, note if you feel better when you leave the building for a day and feel worse after you return.

For more information contact Inspec-Pro Home Inspection at 613.606.1901 or email us at

We Proudly Offer the Following Home Inspection Services