What is a primary function of an air filter?

The primary function of an air filter is to remove contaminants from the air. Air filters are designed to trap particles such as dust, pollen, mold spores, and other pollutants that can be harmful to health or detrimental to the performance of HVAC systems. By filtering out these contaminants, air filters help maintain indoor air quality, ensuring that the air circulating in a space is cleaner and safer for occupants.

In contrast, enhancing the aesthetic appeal of the HVAC system is a secondary benefit, not a primary function. While cooling the air is an important role played by air conditioning systems, it is not a function of the air filter itself. Finally, instructions for setting up the HVAC system pertain to operational guidelines rather than the specific role of air filters. Therefore, the correct answer highlights the essential role that air filters play in promoting good air quality and protecting equipment functionality.