An exterior supply of air to a heating system facilitates combustion by drawing air from the environment outside the structure, rather than utilizing the air already present within the building’s interior. This configuration, often implemented in modern high-efficiency furnaces, ensures a consistent and ample air supply for the burner. As an example, a pipe extending from the furnace to the outside provides the necessary airflow for optimal combustion.
The utilization of an external source of air offers several advantages. It prevents the creation of negative pressure within the building, which can inhibit the proper functioning of other combustion appliances such as water heaters and fireplaces. Furthermore, it can contribute to improved energy efficiency by reducing the infiltration of cold air from outside through leaks in the building envelope. Historically, furnaces relied solely on indoor air, often leading to imbalances in air pressure and reduced heating effectiveness. Modern building codes increasingly favor or mandate external air intake to mitigate these issues and enhance safety.
