Certified Energy Auditor Practice Exam

What is the standard number of air changes per hour considered optimal for energy auditing?

1. 0.25

2. 0.35

3. 0.5

4. 0.75

The correct answer is: 0.35

The optimal standard number of air changes per hour considered for energy auditing is 0.35. This value represents a balance between ensuring adequate indoor air quality and minimizing energy waste associated with heating or cooling a building. When buildings have air change rates that are too high, energy costs can increase significantly due to the continuous need to replace conditioned air that escapes. Conversely, if the air change rate is too low, it can lead to poor indoor air quality, potentially causing health issues and reducing comfort levels for occupants. A value of 0.35 air changes per hour strikes this balance effectively in many scenarios, as it allows for sufficient ventilation without overwhelming the HVAC system or leading to excessive energy consumption. This standard is often utilized in energy audits to assess the performance of a building's envelope and HVAC system. Setting air changes significantly above or below this optimal point can lead to energy inefficiencies or compromised comfort, which is why the choice of 0.35 is recognized as a practical guideline in the field of energy auditing.