Home Energy Rating System (HERS) Rater Practice Exam

Uncontrolled air infiltration refers to the unintended leakage of air into and out of a building, which can significantly impact energy consumption. When buildings are not properly sealed, outside air can enter through various unintentional openings, leading to increased heating and cooling demands. For instance, in winter, cold outdoor air can infiltrate the building, forcing the heating system to use more energy to maintain comfortable indoor temperatures. Likewise, in summer, warm outdoor air can penetrate, causing the cooling system to work harder.

This uncontrolled airflow leads to higher energy usage, as HVAC systems must counteract the temperature fluctuations caused by the influx of outside air. Therefore, the direct effect of uncontrolled air infiltration is indeed higher energy consumption, making it the correct answer to the question. The consequences of uncontrolled air infiltration also include potential effects on indoor air quality and comfort; however, these are indirect effects compared to the straightforward increase in energy consumption associated with heating and cooling.