What is the impact of building tightness on indoor air quality?

The impact of building tightness on indoor air quality is significant, and the need for mechanical ventilation is a crucial aspect of this relationship. A tightly sealed building limits the natural infiltration of outdoor air, which can significantly restrict the flow of fresh air into the indoor environment. While increased building tightness improves energy efficiency by reducing air leakage, it can unintentionally lead to reduced indoor air quality if adequate ventilation is not provided.

In a tightly sealed structure, pollutants from indoor sources, such as volatile organic compounds (VOCs) from furnishings, cooking, cleaning products, and moisture from daily activities, may accumulate more easily without proper ventilation to dilute and remove them. Consequently, mechanical ventilation systems, such as heat recovery ventilators (HRVs) or energy recovery ventilators (ERVs), become essential to ensure a sufficient supply of fresh air and to maintain a comfortable and healthy indoor environment.

Thus, the necessity for mechanical ventilation in tightly sealed buildings underscores the balance needed between energy efficiency and maintaining good indoor air quality, making this choice the most accurate reflection of the impact of building tightness on indoor air quality.