It isn’t news that spiral ducts are gaining popularity in the HVAC industry for their contemporary aesthetic and overall efficiency. So it leads one to wonder what the differences are between oval ducts and rectangular ducts, and why rectangular ducts seem to have one foot out the door.
- Rectangular ducts tend to leak at joints. This means less efficiency. Spiral ducts are self-sealing and therefore don’t leak at duct joints. Since leakage affects overall costs of heating and cooling, rectangular ducts create more expenses than spiral ductwork. Leaks in the duct joints can also mean lower air quality so using self-sealing ductwork equates to fresher air.
- Rectangular ducts have uneven pressure gaps throughout the system which means lower efficiency and higher costs. The sharp turns and pressure differential in rectangular ductwork also creates noise and heavy reverberation. Oval ducts allow air pressure to equalize throughout the ductwork creating a quieter and more economic system.
- Cleaning oval spiral ducts is easier and cost less than the methods of cleaning rectangular ducts. Air-flow measurements performed by the mechanical engineer are made easier with equipment designed specifically for oval ducts, creating better means to monitor and maintain air quality.
- The surface area of rectangular ductwork is significantly higher which creates friction and leads to energy loss. The greater surface area also means more heat is lost through the walls of the duct. Oval ducts have less surface area, so more heat and energy are conserved.
- Rectangular ductwork requires extra space to be factored in around every joint. Connections and reinforcements at the joints can take up to an extra 3 inches. Self-sealing joints remove that need for additional space.
The exposed sheet metal and eye-catching spiral design of the ovoid ducts bring to mind the notion that round ductwork is actually beginning to trend in many buildings. Not only does it create a contemporary finish to many spaces but it also adds efficiency and economic advantage as well. That doesn’t mean they’re a passing fad though.
Besides costs, efficiency, and overall aesthetics, spiral duct products are being fabricated at a much higher rate due to demand. It wouldn’t be ridiculous to think that rectangular ductwork will soon be obsolete and round ductwork will be the only option. So if you’re pondering your choices for ductwork in your building or shop, there really isn’t much to think about.
