Sources of carbon monoxide in the home can be significant, and as a professional home inspector who has completed thousands of heating system examinations, it is astounding the number of times I find a problem with carbon monoxide leakage. Severity ranges, but it is not unusual to find life threatening levels on a fairly regular basis.
Take, for example, an inspection I did several years ago. Upon looking down the chimney of a 25 year old house, I noticed the flue was blocked by a rodent nest. Going immediately down to the furnace, I conducted a simple test to determine the furnace was leaking and carbon monoxide was backing up throughout the house.
I immediately notified the owners so corrective action could be taken. Later, we found out that the homeowner was pregnant and had been experiencing nausea which she attributed to her condition. Subsequent blood tests disclosed elevated levels of carbon monoxide. Her illness was more likely caused by carbon monoxide poisoning.
Carbon monoxide usually leaks into the home due to faulty heating equipment. There are several areas of the heating system where leakage is common. To prevent yourself from becoming a victim of carbon monoxide poisoning, have a qualified heating contractor check your system carefully each year. A thorough examination for sources of carbon monoxide should include the following:
- Heat Exchanger. The heat exchanger keeps the air you breathe separate from the carbon monoxide laced exhaust gases. Check the furnace heat exchanger for any signs of rust, combustion deposits or cracks. If any cracks or holes are found, the furnace should be replaced.
- Vent Pipe. The vent pipe carries exhaust gases to the outside of your house. If the pipe is rusted, loose or blocked, dangerous levels of carbon monoxide can back up into the house. Check the pipe for any sign of corrosion. If the pipe is damaged, replace it immediately. The seams of the vent pipe should also be screwed together to prevent the pipe from separating. Moreover, make sure the pipe clears the roof properly. The vent should be at least two feet higher than any part of the roof within a ten foot radius.
- Chimney. Like vent pipes, chimneys must be free of blockage and properly designed. If you haven't had your chimney cleaned lately, now is a great time to do it. Also, consider installing a chimney cap. This is a steel grate that lets gases escape while keeping the chimney off limits to animals that could build nests inside of it.
- Blower Compartment Door. On the furnace, make sure the door which covers the blower is secure. If the door is loose, bent or damaged, the blower could suck carbon monoxide from the burners and distribute it throughout the house, increasing your risk of carbon monoxide poisoning.
- Flame Color. Proper gas combustion will produce a blue flame. Yellow or orange flames often indicate incomplete combustion, which can release higher levels of carbon monoxide. Also make sure the burners are clean and not covered by rust.
- Combustion Air. All gas and oil appliances need fresh air to burn properly and reduce carbon monoxide levels. If your heating equipment is located in a small room or closet, you may need to add wall, floor or ceiling vents to make sure enough air gets to the equipment. As a minimum, appliances need 1 square inch of ventilation for every 1000 BTU's of heating capacity. An average utility room containing a furnace, water heater and dryer would use about 200,000 BTU's and need at least 200 square inches of vent area.
One of the simplest ways to protect and prevent yourself from the sources of carbon monoxide and carbon monoxide poisoning is by purchasing a carbon monoxide detector. Technology has made these devices inexpensive, simple and reliable. The Consumer Product Safety Commission recommends at least one detector per floor.