Round Duct is the most efficient and economical means of conveying air. When you cannot use round duct because ceiling space is limited or interference from other obstructions, use flat oval duct, which is nearly as efficient.

Round and oval duct have lower initial installed costs than rectangular duct. Their shape results in lower pressure drops, thereby requiring less fan horsepower to move the air and, consequently, smaller equipment. The shape also has less surface area and requires less insulation when externally wrapped. Spiral round and oval duct is available in longer lengths than rectangular duct, thereby eliminating costly field joints. Spiral lock-seams add rigidity; therefore spiral duct can be fabricated using lighter gauges than longitudinal seam duct.

Operating costs are also lower. The smaller surface areas of round and oval allow less heat loss or gain and are therefore more energy efficient. Also, seams and joints are more tightly sealed resulting in less leakage and wasted energy.

The acoustic performance of round and oval duct is superior because their curved surfaces allow less breakout noise.

These ducts not only perform better, they also look better. Many architects and designers are using the aesthetically pleasing shapes of round and oval as unique and integral elements in their designs.

Finally, round and oval duct can help promote healthier indoor environments. Less surface area, no corners and better airflow reduce the chance of dirt and grime accumulating inside the duct and becoming a breeding ground for bacterial growth.