If you want an efficient and high-performing central HVAC system in your Hanover, MD home, you need efficient and high-performing ductwork to support it. HVAC air ducts are the distribution channels that deliver conditioned air to every room. With the right duct materials, you can minimize heat loss and heat gain during air delivery, protect your indoor air quality (IAQ), and limit HVAC noise. Read on to explore the different options in air duct materials and the benefits and drawbacks of each.
Sheet Metal Air Ducts Are the Most Popular Choice
Hands down, sheet metal air ducts are the most popular choice in the nation. They allow for a customized approach to ducting. Sheet metal workers can streamline these features to suit the needs and nuances of individual houses and HVAC equipment types. Some sheet metal materials are lightweight and flexible enough to bend around sharp corners. Flexible sheet metals can also be custom-fitted to suit tight spaces.
Research performed by the University of Florida found that HVAC air ducts can be responsible for the loss of up to 40% of an HVAC system’s heating and cooling energy. Fortunately, with tight fittings and professional duct sealing and insulation, sheet metal air ducts can experience minimal heat gains and heat losses. However, they aren’t without their drawbacks.
All sheet metal air ducts expand and contract when subjected to dramatic temperature and pressure changes. These movements often produce loud popping or banging sounds. If you want whisper-quiet HVAC operation, you might not get it with sheet metal ducting. Proper installation and quality insulation both have sound-dampening benefits, but movement-related sound invariably increases as sheet metal ducts near the end of their lifespans.
Stainless Steel Air Ducts
Stainless steel air ducts are chemical- and corrosion-resistant. They’re strong, highly rigid, and easy to maintain. They work well in hostile environments and in spaces where moving large volumes of air is required. Although stainless steel air ducts are an increasingly common choice for new homes, they’re most often used in commercial construction.
Stainless steel air ducts are the most expensive sheet metal duct type. Their high levels of rigidity also make them unsuitable for tight spaces, sharp corners, and sharply sloped ceiling areas. This is especially true when installing, modifying, or extending HVAC air ducts post-construction.
Galvanized Steel
Galvanized steel is the most durable and longest-lasting option for sheet metal ducting. It’s also significantly cheaper than stainless steel and a bit easier to adapt to tight, cornered, or otherwise awkward spaces. The smooth interiors of galvanized steel ducts are resistant to mold, mildew, and other fungal growths. They also allow for smooth, unimpeded airflow.
Among the many benefits of galvanized steel is its impressive fire rating. Galvanized steel has an A1 fire rating. Thus, these ducts can play an important hand in slowing the spread of fires from room to room.
Unfortunately, galvanized steel is prone to rust and other corrosion. If you have consistently high humidity in your home, galvanized steel ducting could have a relatively short lifespan. To keep galvanized steel ducts in optimum condition, homeowners must:
- Schedule annual HVAC service for all heating and cooling equipment
- Perform regular air filter changes
- Keep the perimeters of their outdoor condenser units clear
- Regularly remove built-up debris from HVAC air vents
These and other ongoing maintenance tasks ensure good airflow and limit significant rises in humidity. Although they’re important for all HVAC systems, they’re critical for preserving galvanized steel ducting.
Aluminum Ducting
Though much less durable than galvanized and stainless steel, aluminum air ducts are valued for being both lightweight and flexible enough for easy installation in tight corners and small spaces. Aluminum ducts are also significantly cheaper than both steel types, and they offer good thermal conductivity. With professional duct sealing and insulation services, homeowners can limit their costs for HVAC air duct replacement and still enjoy high levels of HVAC efficiency.
Like galvanized steel, aluminum is prone to corrosion when installed in humid environments. Moreover, although it’s cheaper than galvanized and stainless steel, it’s more costly than fabric, plastic, and other non-metal ductwork materials. Due to its high malleability, aluminum ducting also requires special tools for installation, especially when this material is used for longer runs of ducting.
Mild Steel Air Ducts
Mild steel (MS) air ducts are often referred to as galvanized mild steel ducts. Like galvanized and aluminum ducts, they have low levels of corrosion resistance and aren’t suitable for humid environments. However, the high rigidity of MS air ducts allows for limited air resistance and promotes even and consistent air distribution.
This metal is incredibly ductile when heated. This makes it perfect for shaping, cutting, and otherwise altering to suit awkward or tight spaces. When used in residential HVAC systems, it’s typically for aesthetic purposes, such as when post-construction air duct installation results in exposed duct sections in visible areas. MS ducting also works well in non-load-bearing walls and other interior frameworks.
Flexible Air Ducts
Often referred to as flex ductwork, flexible air ducts are made from flexible metal, durable plastic, reinforced fabric, or fiberglass. These air ducts are easy to install, low in cost, and flexible enough to suit a broad range of applications. They work exceedingly well in tight spaces and corners. They’re also virtually soundless. Flex ducts are an excellent choice for affordable and all-around quiet HVAC installations. However, flex ducts have shorter lifespans than most rigid ducting. They’re also more difficult to clean.
Fabric Air Ducts
Also known as textile air ducts and air socks, fabric air ducts are porous, lightweight sleeves installed in lieu of metal or fiberglass ducting. Textile ducts are customizable, easy to install, and significantly less expensive than sheet metal. They also allow for even air distribution by preventing radical changes in static pressure. Given that fabric doesn’t expand or contract when exposed to temperature extremes, it’s also among the most quiet ductwork materials currently available.
The drawbacks of fabric air ducts make them unsuitable for some homes and building areas. For instance, they’re less durable than most HVAC air duct types. They’re also more easily entered by pests and damaged by moisture, UV rays, and other exposure.
Fiberglass Air Ducts
Fiberglass air ducts have a lightweight sheet metal construction and a thick interior lining of fiberglass. This offers superior insulation and sound-dampening. Fiberglass air ducts work well in highly corrosive environments due to their excellent corrosion resistance. They’re also mold-resistant. As an inorganic material, fiberglass is less susceptible to mold problems although not entirely invulnerable.
When the fiberglass lining in these ducts gets wet or contaminated with mold or other fungi, the U.S. Environmental Protection Agency (EPA) recommends replacing all affected materials. The intensive cleaning that wet or moldy fiberglass ducts require can shorten their lifespans. It can also dislodge micro-fine particles of glass that enter HVAC systems.
PVC Air Ducts
For high-humidity and corrosion-prone environments, PVC air ducts are an excellent choice. PVC has impressive insulating properties and high levels of moisture resistance. Though not as affordable as flex ducting, it’s less expensive than all sheet metal types. The primary drawback of PVC ducting is its limited heat resistance. Thus, you can’t use PVC if you have a gas-fired furnace for winter heating. However, it does work well with the lower operating temperatures and radiant heating supplied by heat pumps.
We’re proud to offer exceptional heating, cooling, plumbing, and indoor air quality services. We also provide high-quality custom ductwork. If you’re in need of duct cleaning or HVAC maintenance, look into our maintenance program. If you need new ductwork in your Hanover home, get in touch with Beltway Air Conditioning, Heating, & Plumbing today!
