Rooftop package HVAC units utilize economizers for what primary purpose?

The primary purpose of economizers in rooftop package HVAC units is to utilize outside air for cooling during mild weather, which is captured in the correct answer. Economizers are designed to take advantage of favorable outdoor conditions to reduce energy consumption. When the temperature and humidity levels of the outside air are suitable, the economizer introduces this outside air into the HVAC system, allowing it to cool the indoor environment without relying solely on mechanical cooling.

This practice not only enhances energy efficiency by reducing the workload on the compressors but also helps to improve indoor air quality by increasing the amount of fresh air brought into the space. Overall, the use of economizers aligns with energy conservation efforts and cost savings for HVAC operations, especially during certain seasons.

The other options, such as exhausting extra indoor air, equalizing indoor and outdoor pressures, or raising indoor humidity, do not align with the primary function of economizers in HVAC systems. While there are methods for managing air pressure and humidity in a building, the essential role of an economizer is to leverage outdoor air for cooling when conditions permit.