NHIE Insulation and Ventilation Practice Exam 2025 – Complete Prep Resource

A blocked air intake or exhaust in Heat Recovery Ventilation (HRV) or Energy Recovery Ventilation (ERV) systems can lead to increased indoor humidity levels. This occurs because these systems are designed to regulate indoor air moisture and maintain a balanced environment. When air intake or exhaust pathways are obstructed, the system's ability to remove stale or humid air from inside and replace it with fresh, drier air from outside is compromised. Consequently, indoor humidity can rise, leading to discomfort and potential mold growth.

Additionally, higher energy bills can result from this blockage. If the ventilation system is unable to efficiently exchange indoor air with fresh outdoor air due to blocked intakes or exhausts, it may run longer or work harder to achieve proper ventilation, leading to increased energy consumption. This is particularly noticeable in climates where maintaining specific indoor humidity levels is critical for comfort.

Thus, the correct choice highlights that both increased indoor humidity and higher energy bills are potential signs of a blocked air intake or exhaust in HRV/ERV systems, reinforcing the importance of regular maintenance and monitoring of these systems for optimal performance.