Which duct type has the least resistance?

The type of duct that has the least resistance is round duct. This is primarily due to its aerodynamic shape, which allows air to flow more freely compared to other shapes. The circular configuration minimizes turbulence and creates a smoother transition for air movement.

Round ducts offer a consistent cross-sectional area, which helps to reduce friction as the air passes through. This results in less energy being required to push air through the duct system, translating to improved efficiency in HVAC applications and reduced operational costs.

Additionally, round ducts tend to use less material compared to square or rectangular ducts when carrying the same volume of air, which can also contribute to their lower resistance characteristics. The streamlined profile reduces the surface area that air contacts, leading to diminished boundary layer effects that can increase airflow resistance in other duct shapes.

Understanding the benefits and performance of round ducts is crucial for optimizing HVAC system efficiency and effectively managing airflow in various construction and renovation projects.