What is a common reason for reduced airflow in ducts?

Reduced airflow in ducts is commonly caused by blocked ducts, which can occur due to various factors such as the accumulation of dust, debris, or even animal nests within the ductwork. When obstructions are present, they impede the smooth flow of air from the heating or cooling system, leading to decreased efficiency and uncomfortable temperature levels in the space being conditioned. This situation can ultimately result in increased energy consumption, as the system struggles to deliver the required airflow, potentially leading to system strain and higher operational costs.

While high humidity, excessive insulation, and outdated equipment can affect overall system performance, they do not directly cause airflow reduction in the ducts as blocked ducts do. High humidity can impact comfort levels but does not physically obstruct airflow. Excessive insulation pertains more to thermal resistance rather than airflow issues, and outdated equipment may lead to inefficiency but does not inherently block the ducts. Thus, blocked ducts is a straightforward and direct reason for reduced airflow.