What type of ventilation is used in tightly sealed buildings to maintain air quality?

In tightly sealed buildings, maintaining good indoor air quality can be a challenge due to limited airflow. Mechanical ventilation using systems like heat recovery ventilators (HRVs) or energy recovery ventilators (ERVs) is the most effective solution in these scenarios. These systems facilitate the exchange of stale indoor air with fresh outdoor air while minimizing energy losses.

HRVs and ERVs work by transferring heat and/or moisture from exhaust air to incoming fresh air. This process helps to ensure that the indoor environment remains comfortable without wasting energy, which is particularly important in tightly constructed buildings designed for energy efficiency. By continuously ventilating the space, these systems effectively control pollutants, humidity, and temperature, ultimately enhancing air quality.

In contrast, natural ventilation relies on outdoor air currents and is less effective in sealed buildings where openings are minimized. Cross ventilation also depends on wind and temperature differences but similarly struggles in buildings with limited openings. Passive ventilation, while it can help with air movement, does not provide the controlled exchange of air needed for maintaining indoor air quality in sealed environments. Thus, mechanical ventilation systems such as HRVs and ERVs are essential for ensuring healthy air quality in tightly sealed buildings.