Closing Off Your Ductwork to Reduce Carbon-Monoxide Concerns

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If you have a forced-air heating system as well as an air conditioner, then your HVAC systems likely use the same ductwork. This means it is vitally important to your comfort that your ducts remain in great shape. You also want to close ductwork to retain the health of yourself and your family members. If you want to know about some of the health issues that may arise from leaky ducts and how the metal channels can be closed off, keep reading.

Leaky Ducts and Carbon Monoxide 

If you have appliances in the home like water heaters, furnaces, and clothes dryers that run off of natural gas, then the combustion of this fuel will create carbon monoxide as a byproduct. Carbon monoxide is vented outdoors through the ventilation attached to each appliance. In most homes, ventilation systems are attached to one another, and the warm air is vented up and out of the home safely. The venting process occurs naturally as warmer exhaust air rises out of the home. The ventilation relies on a closed system that is pressurized so that warm air can rise completely undisturbed. 

The depressurization of your exhaust or ventilation system can cause serious issues with the way exhaust gasses move away from your house. Depressurization occurs when small holes and openings form in the ductwork and disturb the natural flow of air movement. As air moves in through the holes, the exhaust air may stop traveling up and away from the home. The fan attached to your HVAC system may then pull the exhaust down into the furnace or AC blower. This is called downdrafting or backdrafting, and it can lead to the accumulation of carbon monoxide in your home.

Carbon monoxide is an extremely dangerous gas because of the way it reacts with your body. When you breathe oxygen into the lungs, the oxygen binds to the hemoglobin in the blood that passes through the alveola sacs. Carbon monoxide can also attach itself to the hemoglobin. Unfortunately, the carbon monoxide will not release from the blood as it travels through the body. The blood is then unable to absorb oxygen. This can quickly deprive the heart, brain, and other vital organs of the oxygen you need to live.

Closing Up the Ductwork

The best way to reduce carbon-monoxide poisoning concerns is to make sure that all of the ductwork in your home is completely sealed. This means closing gaps in both the exhaust side of the system as well as the heating and cooling parts of the ductwork. You can close many of the gaps yourself, but you will also need to speak with an HVAC professional about a leak assessment to see whether there are any potential problems in the ducts that are not easily accessible, like the channels that run through the walls and ceilings of your home. 

To start the sealing process, you will need to locate any and all holes in the system that you can see. One of the easiest way to find the openings is to work with a friend and a flashlight. Go into your basement or crawlspace close to where your furnace and AC evaporator are located. Turn off the lights in the basement and ask your friend to shine the flashlight into the closest vent to the HVAC system. Inspect the ductwork, making sure to pay special attention to the seams that connect the parts and pieces of the metal channels. Use a piece of chalk to mark where you see light coming through the ductwork.

If you do not see any light, or if there are no vents near the HVAC system, then ask your helper to remove the air filter from the duct plenum and shine the light through the ducts in this area. Once you find all the openings, spread a thick layer of mastic along each opening to close it. Afterward, make an appointment with your local HVAC professional so a leak-detection test can be completed. The test will indicate whether there are large openings in ducts that are not easily accessible. You can then decide with your HVAC professional whether it is wise to remove some of the walls from your home so the ducts can be accessed and repaired.