Homeowners sometimes hold their breath the first time they turn on their furnace in the fall or winter, wondering if it’s still working after months of idleness. Although the furnace may sound normal and seems to be heating properly, it could be putting out more than just heat. It may, also, be putting out carbon monoxide (CO). Unfortunately, home and business owners often have no idea that their furnaces may be hurting them. Carbon monoxide is a colorless, odorless and tasteless gas that is virtually impossible to detect until it is sometimes too late—hence the name, The Silent Killer.
Although there are other possible sources of carbon monoxide in a home (car left running in a garage, blocked or clogged chimney, corroded or disconnected water heater vent pipe, to name a few), a common source is an unmaintained home gas furnace that suffers from a cracked heat exchanger. The heat exchanger in a furnace is basically a metal chamber, where the combustion process takes place. When this chamber develops cracks or holes from age or poor maintenance, the combustion process is interrupted and CO can be formed. As the furnace blower forces air across the heat exchanger to distribute heat through the duct system to the home, it can pick up this dangerous gas and distribute it throughout the home.
The most frightening thing about CO is that there is no way of detecting it with your senses alone. It will accumulate with no warning. When you are exposed to it, the build-up of carbon monoxide blocks oxygen from entering your body. Without oxygen, your body cannot survive. This makes long exposure to high concentrations of carbon monoxide fatal. The initial symptoms of CO poisoning at 70 parts per million (ppm) are similar to the flu (without fever)—headache, fatigue, shortness of breath, nausea, vomiting and dizziness. When the concentration levels reach the 150–200 ppm range, disorientation, unconsciousness and death are possible.
How does one prevent furnace-related carbon monoxide poisonings? Professional heating contractors make two major recommendations for helping prevent carbon monoxide contamination in homes and commercial buildings. The first is to have the heating system inspected and tuned annually. The tune-up should be very thorough, to include removing and cleaning the burners, testing and verifying that all safety controls are operating properly, the exhaust flue is in good condition and clear of obstructions and a thorough examination of the furnace heat exchanger. Be certain to ask your heating contractor to use a camera scope to visually inspect the entire inside of the heat exchanger to look for cracks and even pin-hole size leaks. Even consider the investment of an annual service agreement. It is a small price to pay for the peace of mind it gives you, your family and co-workers.
The second recommendation is to install a carbon monoxide detector in your home or building. Some newer homes are built with them already installed, but most homes, especially older ones, need to have them added. Most of today’s newer commercial buildings have built-in detectors for this type of gas, but ask your heating professional if you aren’t sure. Older buildings may not have one or may not have enough to adequately cover the entire building. If this is the case, it’s imperative to have one or more installed. These devices vary in price, but residential ones typically run between $40 and $100. They are relatively easy to install yourself, and they may last between five and eight years, depending on brand and model. Your heating professional can be a great source for recommendations, as well.