The ductwork distributes the conditioned air throughout the household. It is the circulatory system for indoor air. However, there isn’t any one-size-fits-all ductwork solution for the air quality and proper temperature distribution.
Depending on performance and installation requirements, cost, and materials, different types of air ducts exist. Knowing about these types can make any homeowners make an informed decision about installation, maintenance, and replacements.
This post will discuss about the different types of ductwork for HVAC systems, their growing trends, issues, and maintenance tips.
Overview of HVAC Ductwork
The ductwork is a network of tubes for delivering and removing air from duct systems.
In an HVAC system, the air conditioner and furnace are responsible for cooling and heating the air. Humidifiers and dehumidifiers control the humidity. The air needs to be sucked in from outside before this treatment and distributed after.
A forced air duct system is the most common way to distribute conditioned air. The ductwork does the job of intake, distribution, delivery, and return for air handler the HVAC system.
Factors to Consider When Choosing Ductwork
Any decision-making process involves considering relevant factors to get the desired outcome. Here are the factors to consider before choosing ductwork:
- Available space
- Building layout
- Airflow efficiency
- Insulation needs
- Noise cancellation
- Cost
- Installation requirements and complexity
- Material properties like durability and moisture resistance
Types of HVAC Ductwork: Pros and Cons Explained
There are four main types of air ducts in an HVAC unit:
A. Sheet Metal Ducts
Sheet metal ducts are made of galvanized steel or aluminum. Galvanized steel is often used for its corrosion resistance in sheet metal ducts.
They can be rectangular or round. The material is rigid and non-porous. This is the most common type used in residential and commercial buildings. Sheet metal ductwork is known for its durability.
The design is long-lasting and the build material offers airflow for long, straight runs. The smooth metal surface of these ducts minimizes friction and maximizes airflow.
Pros:
- Excellent airflow efficiency
- Durable and long-lasting
- Resistant to mold and moisture
- Easy to clean
Cons:
- More expensive than other options
- Requires skillful technician to install
- Improper installations can cause unusual noises
B. Flexible Ducts
Flexible ducts are made of flexible plastic, or metal with wire coil for support. Flexible ductwork is a popular choice for connecting to registers due to its ease of installation. The shape is typically round.
These ducts are highly flexible hence the naming. So, the installation of hvac ducts is straightforward and simple. These ducts are constructed with a metal wire coil for support and flexibility. However, they are more susceptible to damage like tears, punctures, kinks, etc.
They are often used for short runs to the air ducts that connect supply registers to the main ductwork.
Pros:
- Cost-effective
- Easy to install
- Ideal for non-linear layouts
- Suitable for tight spaces
Cons:
- High airflow resistance
- Less durable than rigid types of air ducts for HVAC
- Prone to tears and leaks
- Requires proper support to prevent airflow restrictions and improper installations can still make noises
C. Fiberglass Duct Board
They are made of compressed fiberglass boards. The fiberglass insulation is bonded to a rigid board. The shape is typically rectangular.
The fiberglass duct board is inexpensive yet offers effective insulation and noise mitigation. So, they are often used in large commercial buildings. However, these ducts need proper sealing to prevent the release of small fiberglass particles and material into the air.
Pros:
- Good insulation reduces energy loss
- Excellent noise reduction with sound-dampening properties
- Cost-effective
Cons:
- Susceptible to moisture damage and can harbor mold and bacteria over time
- Can release fiberglass materials into the air
- Requires careful handling during installation and is difficult to clean after the installation
- Not as durable as metal ducts
D. Fiberglass Lined Ducts
They are sheets of metal ducts. The fiberglass insulation is lined internally. The fiberglass ductwork shape can be rectangular or round.
The airflow is better than the rigid ducts. However, being prone to moisture damage is still there.
Pros:
- Good insulation
- Good sound absorption
- Better airflow than duct board
Cons:
- More expensive than unlined metal duct
- Susceptible to moisture damage and mold growth
- More difficult to clean
Check out our infographic on HVAC ductwork types for a visual overview and detailed insights!
Emerging Trends in Different Types of HVAC Ductwork
With different air duct types, the technology is still evolving. In the HVAC ductwork field, some of the growing trends are:
-
Increased Focus on Energy Efficiency and Sustainability
Improving energy efficiency is a key driver in ductwork innovation. Therefore, manufacturers are exploring more sustainable materials for ductwork. The demand for the ductwork to be airtight is also at large.
-
Improved Indoor Air Quality
There is a growing trend of duct materials with antimicrobial and antibacterial properties. Advanced systems like HEPA filters and UV purification are getting integrated into the overall HVAC system.
-
Smart Technology Integration
Smart dampers and zoning systems are getting popular. Different sensors are used to monitor airflow, temperature, and humidity within the ductwork to identify potential problems.
-
Advancements in Ductwork Materials and Design
Apart from the above-mentioned properties, the ductwork material is improving towards lighter and more durable materials. The focus of air duct materials is shifting more towards improved flexibility to fit them into any home design. Manufacturers are exploring 3D design technology to customize ductwork components.
-
Prefabricated and Modular Ductwork
Ductwork components are mostly prefabricated off-site and assembled on-site nowadays. It reduces air duct installation time and costs. Prefabrication also allows for better quality control of the ductwork.
Common Issues with Ductwork
The ductwork is hidden inside the walls and ceilings. It is prone to various issues that are not observable from the outside. These issues can impact HVAC system supply duct‘s performance and energy use. The indoor air quality can also be affected by the condition of the ductwork. Bad air duct seals can significantly reduce the efficiency of your HVAC system.
Some of the common issues with ductwork are:
- Air Leaks: This is the most common occurrence. Joints, seams, and tears in the ductwork are the most prone to leaks. Leaks reduce the HVAC system’s efficiency and uneven temperatures in the room.
- Improperly Sized Ductwork: This is caused when the installation is not taken care of by a properly experienced technician. If the ductwork is small, it restricts airflow. Larger than required ductworks cause inefficient airflow.
- Poor Insulation: Unconditioned spaces like attics or crawlspaces need proper insulation. Otherwise, the duct leaks heat in the winter and gains heat from outside in the summer.
- Kinks and Bends: Improper installation is the main cause of this. Too much movement in the flexible ducts also causes bends and kinks. This issue reduces the airflow.
- Duct Damage: Some damage in the duct includes tears, punctures, or crushed sections. They are caused by pests, moisture, or accidental damage.
Maintenance Tips for Ductwork
Clean ducts are mandatory regardless of types of HVAC air ducts you select. Proper maintenance allows for cleaner and better air as well as higher efficiency. Here is how to maintain the duct systems:
- Dirty air filters directly impact the air passing through the duct. Regularly change them. Proper ductwork is essential for maintaining good indoor air quality.
- Inspect for leaks regularly. Seal them to minimize heat transfer outside.
- Insulate ducts properly in unconditioned spaces by a professional.
- Blocked vents and registers restrict the airflow including the duct. Make sure they are unobstructed by outside things.
- Have your ducts professionally cleaned as needed. Always hire qualified personnel if you have respiratory issues, mold growth, or pest infestation.
- Seal openings or cracks in your home’s foundation or walls so that pests and rodents can’t enter your home and ductwork.
- Avoid storing items against ductwork to prevent damage.
Conclusion
While choosing the right one from various types of ductwork for your HVAC system, go over their qualities and select one that matches your requirements and household or building type. Rigid ductwork, such as sheet metal ductwork, is often preferred for its durability. Sheet metal ducts are a common choice for many homeowners. Rigid ductwork offers superior airflow compared to more flexible ductwork options.
If you are still confused about which type of ductwork is the best option for you, you can consult with HVAC service experts. They can assist you in choosing the right ductwork based on your property’s design outline, space, and budget. Also, your ductwork will need maintenance and cleaning. Overall, it is better if you let professionals install them, as they know which type of ductwork is the most convenient and suitable for you.
