A jalousie window with wide slats is a single panel window design that features horizontally mounted slats that can be adjusted to control ventilation and sunlight. These slats can be constructed from different materials, such as glass, wood, or metal, and are operated using a crank or lever. By turning the crank, the slats rotate to allow for greater airflow and natural light.

While wide slats offer maximum ventilation, they can also result in air leakage, leading to higher heating and cooling costs. Such windows are commonly used in warmer and more humid climates where ventilation is critical but may not be as effective in colder areas due to the potential for increased energy loss.