4 Main Types of HVAC Ducts & the Pros & Cons of Each
Unless you’re living and working in a single, one-room log cabin in the middle of the woods, chances are your construction project requires a network of air ducts to regulate the temperature throughout your residential or commercial building.
Selecting the right type of HVAC duct for your heating and cooling system requires special knowledge of the type of unit, the size of the building and the mapping of the ductwork through the walls and ceilings. Other factors, like material durability and flexibility and, of course, price point can have an effect on indoor air quality, energy efficiency and, ultimately, your decision. With all these variables to consider, you might feel a little hard-pressed to make a decision. Parts Town can help point you in the right direction with our list of the 4 main different types of HVAC ducts and the pros and cons of each.
Sheet Metal Ducts
- Material – Typically made out of galvanized steel or aluminum, they offer a longer-lasting, sturdier solution to flexible or fabric ductwork.
- Popularity – Sheet metal vents are one of the most common and widely used types of HVAC ducts.
- Energy efficient – With the proper sealing, they can also be the more energy-efficient option as well, which can reduce their workload and prevent unnecessary wear and tear.
- Fire & pest resistant – They're also fire and pest resistant, making them a go-to choice in industrial settings where the risk of fire is a concern.
- Cost – What’s not to like, you might ask? Sheet metal ducts fall on the higher end of the price spectrum.
- Lifespan – On the other hand, they can last more than 25 years, so this cost is fairly preliminary.
- Mold & mildew resistance – The good news is that sheet metal ducts are resistant to mold and mildew growth.
- Condensation – The bad news is that improperly insulated ones are prone to condensation, which can cause mold and mildew growth in the surrounding areas.
- Noise – They also can be noisy, as the rigid material provides the ideal medium to transmit operational sounds, like blowers and fans, through vibration.
Flexible Ductwork
- Material – It gets its tell-tale slinky shape from metal wiring wrapped with plastic and insulated against thermal loss.
- Noise – Because of this, they are generally a lot quieter than other ductwork on the market.
- Setting – Flexible ductwork is ideal for small, tight spaces because it can be easily installed around corners and support beams without a ton of fittings or connectors. This type of HVAC duct is typically seen in low air-volume homes or buildings or as a branch connection to individual rooms or hard-to-reach places.
- Mold & Mildew – The reason this type of HVAC vent isn’t installed in larger buildings is because it’s less durable than sheet metal alternatives and prone to mold and dust accumulation, which can make it less than ideal for humid environments.
- Short distances – They also aren’t the most effective over long distances, as they can bend, sag and kink, which can restrict airflow and reduce the efficiency of the HVAC system.
Fiberglass Lined Ducts
- Material – These types of HVAC duct systems can be made out of sheet metal or other material that is lined with fiberglass as a solution to thermal loss and noise.
- Setting – For that reason, it’s often implemented in industrial settings with considerable air cooling or heating demands.
- Reduces condensation – The fiberglass lining can also fix the condensation problem with sheet metal ducts.
- Mold & mildew – Fiberglass is porous, making it susceptible to mold and mildew growth while being difficult to clean.
- Cost – If you’re looking for a cost-effective alternative, fiberglass-lined ducts aren’t it. The cost of the material and manufacturing is more expensive than flexible, sheet metal or fiberboard ducts.
- Health concerns – The biggest drawback of fiberglass-lined ducts is the concern about its deterioration. Fiberglass is extremely harmful to respiratory health and can exacerbate asthma and bronchitis in susceptible people.
Fiberboard Ducts
- Material – Fiberboard ducts are a type of HVAC duct that uses compressed fiberglass fibers bonded with resin to insulate against heat loss.
- Sound dampening – Like fiberglass lined ductwork, fiberboard ducts are also very effective at reducing operation HVAC system noise.
- Mold & mildew resistant – Even though the fiberboard ducts have a porous surface, they’re resistant to mold, mildew and moisture because of their exterior foil laminate.
- Cost – They’re also more cost-effective than metal ductwork and don’t require insulation.
- Airflow resistance – Due to the porous and rough material of the resin-covered fiberglass, it creates more air resistance, decreasing its efficiency in air ventilation.
What Is the Most Common Ductwork?
The most common type of HVAC ducts is the sheet metal ducts because they’re made from durable materials like aluminum or galvanized steel that possess smooth, non-porous surfaces resistant to mold growth, which as you’re probably already well aware is one of the main reasons buildings are condemned. They can also be easily installed and sealed against air leaks, making them the ideal choice for residential and commercial buildings.
What Is the Most Efficient Duct System?
Efficiency in an HVAC system is an important consideration, for it can have a high impact on the price of your utility bills, the ability to maintain stable temperatures and the frequency of repairs. It’s also a significant selling point when building new homes or buildings, upgrading outdated or broken air conditioners and anticipating future environmental legislation.
Several factors can affect the cooling, heating and energy efficiency of your HVAC system, including the ductwork layout, materials, quality of installation and whether you’re up to date on preventative and seasonal maintenance.
All things considered, sheet metal ducts, when properly installed and insulated, provide the most energy efficiency and airflow. As previously mentioned, their smooth, non-porous surfaces reduce friction and air resistance, making them one of the best types of air ductwork to use for environmental and cost-conscious applications.