How Ductwork Affects HVAC Performance

Air ducts are an essential part of a conventional HVAC system, carrying the heated or cooled air throughout the home and into each room. A properly designed and installed duct system keeps the home comfortable while minimizing utility costs and energy losses.

If the ductwork is poorly installed, it can have a huge impact on the performance of the HVAC system and the comfort of the home.

How Do Air Ducts Work?

An air conditioner, heat pump, or furnace draws in air from the return ducts using a large blower fan, and then the air is cooled or heated, depending on the season. After the air leaves the furnace or air conditioner, it goes through a plenum, which connects to the main ductwork. The air travels through one or more trunks that are connected to the plenum, then through individual branch ducts that go to each room or zone.

Several strategically placed return ducts collect air from throughout the home and bring it back to the HVAC system to begin the cycle again. Ideally, the supply and return airflow should be balanced throughout the home and in each room or zone to avoid positive or negative pressure areas. Dampers can be added to adjust the amount of air that flows into each room.

Common Types of Ductwork

The most common types of ductwork in the Palm Beach area include:

  • Galvanized steel: Galvanized ducts are made from sheet metal formed into rectangular or tubular ductwork. The zinc coating provides long-lasting corrosion resistance, and when sealed properly, galvanized ducts can be quite efficient. In non-conditioned spaces, fiberglass duct liners can be added to the interior, or fiberglass wrap can be used on the exterior to insulate the ducts.
  • Aluminum ductwork: Like galvanized steel, aluminum ducts are made from sheet metal formed on or off-site. Aluminum ducts are lighter than steel ducts, but they offer similar strength, durability, and performance.
  • Fiberglass ductwork: Made from sheets of fiberglass with built-in insulation, fiberglass ducts offer impressive thermal performance, along with noise reduction.
  • Flexible ducts: Made from a wire coil covered with plastic and insulated with fiberglass, flexible ductwork is quick and easy to install while offering good thermal performance and noise reduction. Flexible ducts can be used as the final connection between rigid ducts and the output vents, or they can be used as the primary ductwork.

The Importance of Proper Duct Installation

When ductwork is not properly installed, it can suffer from airflow problems, heat loss, heat gain, excessive vibration, and more. This can reduce the level of comfort in your home as well as the performance of your HVAC system, leading to higher utility costs or even HVAC breakdowns.

For a smooth-running, efficient HVAC system, proper installation is essential. Here are some of the key principles of good duct design and installation:

  • Proper sizing: Sizing by rule-of-thumb estimates often results in poor HVAC performance. For the greatest comfort and efficiency, the HVAC system should be sized using ACCA Manual J load calculations, and the ductwork should be designed using ACCA Manual D procedures. These account for far more factors than just the size of the rooms and the square footage of the home.
  • Duct installation: Air ducts should be installed with runs that are as straight and short as possible. The number of tees, elbows, and bends should be kept to a minimum, and to minimize noise transmission, flexible ducts should be used to connect rigid ducts to the output vents. If flexible duct is used for the entire duct branch, it should be routed to avoid pinching, kinking, crushing, or sharp bends. All ducts should be fully supported by hangers to keep connections tight and minimize vibrations.
  • Duct sealing: All joints in the ductwork should be securely fastened, and they should be sealed using the appropriate foil tape or mastic for the application.
  • Duct insulation: Whenever possible, ducts should be placed in conditioned space to minimize heat loss and heat gain, but if they must be placed in conditioned space, they should be thoroughly insulated with fiberglass wrap or other suitable products.
  • Things to avoid: Bare wall cavities, soffits, or plenum space should not be used for supply or return airflow, only physical ducts. To avoid backdrafts and carbon monoxide poisoning, return vents should not be placed near fuel-burning appliances or flues.

Expert Air Duct Design & Installation in the Palm Beach Area

When you want to maximize the performance of your ductwork and HVAC system, choose our team at Hopkins Air Conditioning for professional duct design, fabrication, and installation. Our company is the leading ductwork installer in West Palm Beach, and we’ve served the area since 1988.

We are NATE- and NCI-certified, and we will devote all the time and effort necessary to ensure your finished ductwork offers exceptional performance, efficiency, and comfort for your Palm Beach home.

Call 561-656-4870 or contact us online to request your ductwork installation quote today.

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