Occasionally we hear about a devastating incident where people are poisoned by carbon monoxide. Many times people die. All of these situations are preventable, but adequate precautions are still lacking in many homes today. Even more common, but less recognized, are cases of mild to moderate exposure to carbon monoxide.
Mild exposure to carbon monoxide can cause a variety of symptoms including: shortness of breath, mild nausea, and mild headaches. Moderate exposure can cause headaches, dizziness, nausea, and light-headedness, with the possibility of death if exposure persists for long periods of time. What can cause mild or moderate exposure to carbon monoxide? Read below to see how negative air pressure can contribute to carbon monoxide poisoning within the home.
Clothing dryers have a powerful fan that moves fresh air from inside the home into the dryer where it is heated. The heated air is then directed over the clothes where moisture is extracted. The moist hot air is now ducted outside the home through the dryer vent. If fresh replacement air is not allowed to enter the home through a partially open window or other opening, negative pressure results.
Bathroom vent fans are designed to do one thing, remove air from the home for the purpose of removing odor and/or moisture laden air from the shower. Multiple bathrooms and fans result in more air being removed from the home resulting in negative air pressure.
Kitchen vent fans are designed to remove smoke and cooking odors. Since air is exhausted from the home, negative air pressure results if sufficient replacement air is not made available.
Externally vented gas furnaces and water heaters produce carbon monoxide that is normally vented outside the home through flue pipes. Since the combustion gases are hotter than the surrounding air, they tend to rise with the help of gravity through the pipe and outside the home. These appliances also contribute to negative air pressure.
If a home has negative air pressure, it is possible for gas fired furnaces and gas fired water heaters to poison the home with carbon monoxide.
Modern homes are built to be more air tight than in the past, thus making it more difficult to replace air that is exhausted by appliances in the home. In a tightly sealed home, if a window or other opening is not partially opened to allow fresh air to enter while vented appliances continue to operate, the result is negative air pressure in the living area. Negative air pressure can cause replacement air to enter the home in ways that are usually not suspected of being a problem. Some are listed below and how they contribute to negative air pressure.
Most gas appliances such as gas fired furnaces and gas water heaters rely on a flue pipe that vents the combustion gases out of the home through the use of gravity. Since the flue gases are hot and lighter than air, they tend to rise; hopefully within the flue pipe which carries the gasses through the roof and out of the home. The problem arises when the home is under enough negative air pressure to overcome the effect of the gravity induced draft in the flue pipe. Excessive negative air pressure actually overides the effect of gravity in flue vent pipes designed to carry poisonous gasses out of the home. Instead of combustion gases going outside, fresh air from the outside is actually forced down the vent pipes and into the living space near the gas appliance. The result is that carbon monoxide and other poisonous gasses are distributed through the home.
Besides the symptoms of carbon monoxide exposure listed above, other health issues may develop over time. We all know people with allergies to food, pollen, and mold, but carbon monoxide poisoning can cause a condition known as multiple chemical sensitivity which in turn can mimic the symptoms of many diseases after casual exposure to a particular chemical or combination of chemicals. Some people react to the air when shopping for detergents, pestcides, furniture, or building materials.
While it's inconvenient to avoid shopping in areas with strong chemical odors, it can be a real hardship if an individual is unable to tolerate the air in their own home. Cooking odors, scented candles, fabric softeners, and new carpet can cause issues if steps are not taken to remove the offensive chemicals. A quality air purifier such as an Austin Air Healthmate contains activated carbon and is designed to remove over 3000 common chemicals from the air. The Healthmate also contains 60 sq. ft. of true HEPA filter media to remove pollen, mold, and viruses. To top it off, Each Austin Air Purifier has two pre-filters designed to increase the filter change interval to five years. All machines are covered with a Five-Year Warranty. For a complete selection of air purifiers by Austin Air, visit Clean Surroundings where you get free ground shipping to addresses within the continental USA.
I have recently been diagnosed with chronic low level carbon dioxide poisoning that has to be occuring in my home. We have been at a loss to identify the cause, as the furnace checks out ok, etc, etc. This article well explains how this house could have become a sick house since we moved in 2 years ago: addition of kitchen and bathroom vent fans, sealing up cracks where cold air was coming in during winter months, using a clothes dryer whereas the previous tenant did not have one. I am hoping that this article will help convince the landlord to purchase and air purifier and some plants for us, so that I don't have to go thru the rest of the winter with the windows wide open. Thank you so much.
If your home is sealed that tight, it may be best to open a window slightly when operating vent fans, clothes dryers, etc. The flue on water heaters and furnaces does require some air, usually replaced by leaks around doors and windows. Air infiltration is healthy, although it does increase heating and cooling bills. There's nothing like fresh air.