Which of the following best describes the purpose of an air filter in HVAC systems?

The primary purpose of an air filter in HVAC systems is to trap airborne particles and improve air quality. Air filters are designed to capture dust, pollen, pet dander, mold spores, and other particulates from the air circulating through the system. This process not only enhances the comfort of indoor environments but also protects the HVAC system's components, such as the evaporator coils and blower, from accumulating dirt and debris, which can impede performance and efficiency.

By maintaining good air quality through filtration, air filters help reduce the presence of allergens and irritants in the living space, which is particularly beneficial for individuals with respiratory issues or allergies. Effective air filtration is a critical component of HVAC systems, ensuring that the air we breathe is cleaner and healthier.

The other options focus on functions that do not align with the primary role of air filters in HVAC systems. While generating heat, reducing noise, and controlling humidity are important aspects of HVAC operation, they do not pertain to the filtration process and air quality improvement that filters provide.