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Which Type of Metal Duct Is Better: Rigid or Flexible Aluminium?

Metal Duct Is Better: Rigid or Flexible Aluminium?


Metal ducts are a popular choice for both commercial and residential structures due to their efficiency in air distribution and ability to control sound transmission. When deciding which type of metal duct is better: rigid or flexible aluminium ducts, each option has its advantages and drawbacks.

Choosing the right type of metal duct ultimately depends on the specific application and requirements. Rigid aluminium ducts are favored for their durability, recyclability, and lightweight characteristics. Conversely, flexible aluminium ducts offer resistance to damage and are easily installable in confined spaces.

Benefits of Rigid Ducts:

The primary advantage of installing rigid metal ductwork in a residential setting is its exceptional durability. Rigid ducts withstand heavy air pressures without sagging and can support the weight of multiple bends. They are resistant to cracking, splitting, or leaking when cut during installation or repair. Once adequately sealed to prevent outdoor air infiltration into conditioned spaces, rigid ducts provide years of reliable service with minimal maintenance requirements.

HVAC contractors have relied on rigid metal ducting for over a century. Technological advancements have enhanced its performance and efficiency, ensuring compliance with building codes without size restrictions. Installation costs remain reasonable, contributing to its continued popularity.

Benefits of Aluminium Flex Ducts:

Homeowners often prefer flexible aluminum over other materials due to its lightweight nature and ease of handling. Cutting holes and installing fittings is simpler with flexible aluminum than with rigid materials, requiring only one person to handle a roll instead of two heavy metal rolls. Aluminium is both lightweight and easy to bend compared to materials like stainless steel. Additionally, aluminium resists corrosion and oxidation, preventing rust or corrosion indoors. Its UV-resistant properties make it naturally protective against outdoor elements.

Flexible aluminum ducting has been utilized by HVAC contractors for over 50 years. Manufacturing improvements have enhanced the efficiency and affordability of adjustable aluminum, particularly for larger sizes. Technological advancements have extended the lifespan of flexible ducts by up to 40%. The surge in popularity is attributed to its smooth interior surface reducing pressure loss and its lightweight design compared to alternatives such as galvanized steel. While manufacturers claim rigid metal ducting outperforms flexible aluminium, supporting data is often lacking. Although typical duct losses for flex ducts may be higher than rigid metal ducting, architects and engineers often overlook these losses when designing new structures.

Choosing the Right Metal Duct:

The decision between rigid and flexible aluminum ducting depends on individual needs and HVAC system expectations. For those seeking highly durable materials with long-term reliability, rigid metal ducts may be the preferred choice. On the other hand, individuals requiring a lightweight option that is easy to install in existing homes without altering framing members and outlets may find aluminium more suitable.

It’s essential to note that if a heating and cooling contractor suggests flexible metal ducting is no longer viable due to code violations, verification with local building codes is advised. Many areas have revised ordinances to permit flex ducts up to 6 inches in size, provided they are correctly installed.

Conclusion (Metal Duct Is Better: Rigid or Flexible Aluminium)

Ultimately, the choice between rigid and flexible aluminium ducts depends on individual preferences and specific needs. Both types offer benefits that may cater to different requirements. If uncertainty persists or questions arise, seeking guidance from professionals can assist in making the best decision for homes or offices.

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About the author


I am Ben , a seasoned HVAC specialist with over 6 of experience in the HVAC industry. I holds HVAC Certification and has a proven track record in providing expert advice on HVAC systems.

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