Natural draft is a method of moving air or gases through a system without the use of mechanical fans. It relies on the natural buoyancy of warm air, which rises and creates a pressure difference. This pressure difference allows cooler air to enter from lower areas, facilitating ventilation in spaces like chimneys or ventilation shafts. In buildings, natural draft can help regulate indoor air quality and temperature. It is often used in fireplaces and stoves to draw smoke and gases outside. This passive system is energy-efficient, as it does not require electricity to operate, making it an environmentally friendly option.