If you want to maximize your HVAC system's efficiency, it's worth considering flexible ducts. Ducts without leaks are significantly more efficient, which translates to lower energy bills and a better-performing HVAC system. Unlike other types of ductwork, flexible ducts don't need additional sealant.
It's also possible to use metal and flexible ducts for your HVAC system; this way you can reap the benefits from both types of ductwork.
Disadvantages of Flex Duct
Flexible ducts are more prone to air leakage around the seams, which can lead to lower HVAC system performance. Additionally, the pliable nature of flex duct tends to make them prone to tangling or crushing when they pass through tight spaces or fixtures.
Properly installed and well-maintained sheet metal, PVC, or insulated ducts can last 20 to 30 years, while flexible ducts have a shorter lifespan of 10 to 15 years.
There are several types of piping used in HVAC systems: Copper Pipes: These are the most common for refrigeration systems due to their high thermal conductivity and corrosion resistance. Steel Pipes: Mainly used for heating and hot water systems due to their strength and durability.
Type L Copper Pipe
It is widely used in both residential and commercial AC installations. Advantages: Versatility: Type L pipes are suitable for a wide range of applications, from residential to light commercial use. Cost-Effective: More affordable than Type K pipes while still offering good durability.
Ducts are conduits or passages used in heating, ventilation, and air conditioning (HVAC) to deliver and remove air.
Flexible ducts are made of lightweight materials and quick and easy to install. This means they're a cheaper alternative to rigid ductwork and there's less downtime during installation. The other advantage to flexible ducts is they can be formed to fit in areas where it's impossible to install rigid ducts.
Friction is the enemy of airflow. Unlike rigid ducts, which are cut to length within a tolerance of 1 inch or less, it's easy to cut a length of flexible duct that's several feet longer than is needed to get from point A to point B. That creates slack in the duct, which reduces airflow for two reasons.
While it's clear that sheet metal ducts may be the most energy-efficient ductwork due to the lower chance of damage and deterioration, each home has unique needs when it comes to its HVAC setup. Some homes may not be able to accommodate the space needed for sheet metal ducts, for example, due to tight spaces or bends.
Loud Noises: One of the first signs of flex pipe failure is a loud rumbling noise. If there's a crack in your flex joint, it will sound like you have an excessively noisy engine. The exhaust flex joint may also produce a hissing or tapping sound that gets louder the faster you go.
Over time, dust and debris can build up in the ducts, affecting the efficiency of your system. While you may be familiar with cleaning rigid ducts, you may wonder if flexible air ducts can be cleaned. The answer is yes, but to avoid damaging the ducts, you should hire a pro to clean them.
Steel duct systems are the easiest to clean and will not rip or tear in the process, as polyester flexible ductwork would.
Duct Replacement Cost by Home Size
Larger homes require more materials and labor to replace the entire duct system. On average, the cost ranges from $2,000 to $5,000 for a small to medium-sized home. However, duct replacement can run as low as $1,400 for smaller homes and as high as $9,000 for larger homes.
Fiberglass is a common choice for duct insulation due to its excellent thermal and acoustic properties. It effectively reduces heat transfer and dampens sound, making it ideal for both commercial and residential HVAC systems.
❖ The length of flexible air ducts is not limited, unlike flexible air connectors, which are limited to 14 feet (4267 mm) (see commentary, Section 603.6. 2.1).
DIY Airflow Fixes
Check the vents in each room to ensure they are all open and directed appropriately (if you have adjustable louvers). Dirty, clogged filters can impede airflow as well. Be sure to replace these regularly. Pros suggest 1-6 months depending on the type of filter you have.
My colleague John Puryear teaches the simple “2 Foot Rule” for takeoff placement in his classes. When there is a change in air direction in a duct, it takes roughly 24 inches for airflow to restore its pattern. Because of this, John recommends keeping takeoffs 24 inches away from any turns, transitions, or the end cap.
You might be wondering, "Can you use flexible ducts for HVAC systems?" The short answer is yes, but it depends on the type of heating or cooling system your home uses, your house's current layout, and various other factors.
Galvanized steel is a great duct material because it is durable and non-porous. These qualities can help keep your HVAC system healthy and mold-free. Rigid ducts can also be made of aluminum, which has similar benefits but is more lightweight.
Flexible ducts are an increasingly popular option due to their simple installation process and lower cost compared to metal ducts. They are created with materials like fiberglass, vinyl, or reinforced fabric, making them lightweight yet durable enough for most residential applications.
This type of flexible duct can withstand temperatures up to -400° F at a minimum, and 1650° F at maximum.
Sheet metal ducts
It is the most common kind of air duct and normally they are made of galvanized steel or aluminum. One advantage of the latter is its lightweight compared to other air ducts materials.
Yes, flexible ductwork can be cleaned. However, it is important to use the proper techniques and equipment to avoid damaging the ductwork. Professional duct cleaning companies have the experience and expertise to clean flexible ductwork safely and effectively.
Experts advise having your air ducts cleaned every 2 to 3 years to prevent many maintenance and health problems before they start. However, homes with pets or children with allergies should have their air ducts professionally cleaned more frequently than the recommended average.