Nate Core Practice Test 2025 – Comprehensive Exam Prep

The selection highlights that dirty filters and poorly insulated ducts are significant contributors to poorly performing HVAC systems. When filters become clogged with dust, dirt, and debris, they restrict airflow. This impedes the system’s ability to circulate air effectively, resulting in inefficiencies and potential strain on the HVAC unit. Similarly, poorly insulated ducts can lead to significant heat loss or gain as air travels through them. If the ducts are not adequately insulated, the conditioned air may lose temperature or gain unwanted heat en route to its intended location, leading to additional energy waste and discomfort in the space being conditioned.

In contrast, excessive sunlight can affect indoor temperatures and comfort levels but does not directly correlate with the HVAC machinery's performance itself. Frequent service checks and regular filter changes are beneficial practices that enhance the system's performance, ensuring it operates efficiently. Therefore, these options do not contribute to the poor performance of HVAC systems.