Air Systems Cleaning Specialist (ASCS) Practice Exam

When assessing duct leakage in a residential HVAC system, what might cause a significant energy loss?

1. Excessive insulation

2. Improper duct sealing

3. Correct sizing of ducts

4. Well-designed air distribution

The correct answer is: Improper duct sealing

Improper duct sealing is a primary cause of significant energy loss in a residential HVAC system. When ductwork is not properly sealed, air can escape through gaps, holes, and unsealed joints. This leakage can lead to a decrease in efficiency as the HVAC system works harder to maintain the desired temperature within the home. The loss of conditioned air not only makes the system less effective but also increases energy consumption and costs, as the system may run longer than necessary to compensate for the lost air. In contrast, excessive insulation does not directly relate to energy loss from duct leakage; instead, it generally contributes to energy efficiency by reducing heat transfer. Correct sizing of ducts and a well-designed air distribution system also improve the efficiency of HVAC systems, ensuring that airflow is optimized and reducing the likelihood of energy loss. Proper duct design and sealing are essential to maintaining system performance and minimizing energy waste.