Ordinarily, a heating system should draw fresh air from the surrounding and expel spent gases through the exhaust flue. Backdrafting occurs when the opposite happens. In backdrafting, the heating system draws air from the exhaust flue and spews stale gases into the house.

Backdrafting is dangerous since it fouls up your indoor air and can lead to carbon monoxide poisoning. Here are some of the common causes of backdrafting, and their solutions.

Improper Installation and Design

A properly designed heating system should draw fresh air and expel stale gases through the flue. However, malfunctions or defects can interfere with this unidirectional airflow and trigger backdrafting. Here are some of the malfunctions or defects that can trigger backdrafting:

  • A small flue that cannot handle all the spent gases — some of the gases will have to flow back into the heating system and into the house
  • A blocked flue that is restricting the flow of flue gases out of the house
  • A cracked flue that is spilling gases inside the house

Anything that interferes with the flow of gases through the flue can trigger backdrafting. Ensure you hire professional heating contractor services to design your heating system so that it gets the right flue size. After that, observe proper maintenance so that nothing blocks the flue, and you fix flue damages as soon as they occur.

Inadequate or Improper Venting

Sealing your home is great for efficient heating and cooling. However, a perfectly sealed house is in danger of backdrafting. You need to seal the house but vent it adequately so that stale gases can still get out of the house.

Proper venting is even more crucial if you have multiple combustion gases in the house, and they use common venting.  The combustion appliances can overwhelm the common vent and overwhelm your house with spent gases.

The solution is to ensure proper venting of all combustion appliances in the house. For example, all combustion processes in the house should exist in closed systems with direct and powered venting out of the house.

Ensure Pressure Balance

Lastly, your house can also experience backdrafting if the pressure inside the house is lower than the pressure outside the house. The depressurization is possible since heating systems draw a lot of air. If the house is depressurized, it can draw air through all openings, including the vents that are supposed to expel gases out of the house.

You can ensure pressure balance by minimizing the combustion systems in the house. Do this by using adequately sized exhaust fans and balancing airflow in HVAC (heating, ventilation, and air conditioning) systems.