Which system is typically more common in newer, tightly sealed homes?

Mechanical ventilation is typically more common in newer, tightly sealed homes because these homes are designed to be highly energy efficient, minimizing air leaks that could compromise heat retention and overall energy performance. This sealing leads to reduced natural airflow, making it essential to incorporate a mechanical system that can effectively introduce fresh air and remove stale air. Mechanical ventilation systems can include exhaust fans, heat recovery ventilators (HRVs), and energy recovery ventilators (ERVs) that help maintain indoor air quality while controlling humidity and temperature.

In contrast, natural ventilation relies on the movement of air through windows, doors, and other openings, which is not as feasible in homes designed to be tightly sealed. Passive ventilation utilizes architectural elements for airflow without mechanical assistance, and cross ventilation depends on wind flow between opposing openings, both of which are limited in their effectiveness in modern airtight constructions. Therefore, mechanical ventilation is critical for ensuring adequate indoor air quality and comfort in new homes that prioritize energy efficiency through tighter seals.