What is a common indicator of a clogged air filter?

A common indicator of a clogged air filter is increased energy bills. When the air filter becomes clogged with dust, dirt, and other particles, it restricts airflow in the heating, ventilation, and air conditioning (HVAC) system. As a result, the system has to work harder and run longer to achieve the desired temperature, leading to higher energy consumption. This extra workload can significantly increase utility costs over time, making it an important sign to monitor.

Other indicators like unusual noises, smells from the vents, and high indoor humidity may signal various issues. For example, unusual noises could indicate mechanical problems, odors might be related to mold or electrical issues, and high humidity levels can be caused by an inefficient cooling system or poor ventilation—not solely from a clogged air filter. Thus, while these symptoms can indicate problems within the HVAC system, increased energy bills are specifically tied to the decreased efficiency caused by a clogged air filter.