<p>As the world is shifting toward sustainable and energy-efficient building practices, the use of smart windows is becoming prevalent in modern construction, especially in the areas of Passivhaus. These windows can dynamically regulate the access of light and heat in buildings, efficiently control indoor temperatures, and minimise reliance on artificial heating and cooling systems, resulting in a more sustainable and comfortable living environment. This article provides a detailed summary of current research and case studies on smart windows as a vital component capable of dynamically changing solar radiation and heat gain. It demonstrates how integrating smart windows can increase energy efficiency and overall building performance while providing a more aesthetically pleasing and comfortable living experience. There is an in-depth discussion of the advantages that may be gained by installing smart windows, including a decrease in the amount of energy used, an increase in comfort, and an enhancement of the air quality within the building. This study provides a fair and comprehensive review of smart windows in passive and net-zero buildings to inspire architects, builders, and academics to use this fast-expanding technology to design sustainable and energy-efficient structures.</p>