a graphic of a stick figured jumping into the frame from the left side with jumper ducts behind it in a wood framed open home

Have you ever wondered how air flows between the rooms in your house? Sure, you have an air register in each room, but how does the air get there? The answer lies in jumper ducts, but what are they?

Jumper ducts (AKA jump ducts) facilitate the flow of air from one room to another. They’re efficient since they shorten the distance air travels and minimize energy losses due to friction and heat exchange.

In this article, I’ll help you understand what jumper ducts are, how they work, and why they’re efficient. I’ll also discuss how to improve their efficiency and the principle that governs their design, so check it out!

Jumper Ducts in HVAC: What Are They and How Do They Work?

A jumper duct is an insulated flexible duct that runs between two registers in a home. It’s usually positioned in the attic and takes up very little space.

Jumper ducts work by opening and closing to regulate the air flowing through them. They have small holes in them that allow air to flow through. By regulating the airflow, they control the temperature in the room.

Jumper ducts are an essential part of HVAC systems. While they may look like simple tubes, jumper ducts have the following functions:

  • Jumpers (or jumps) connect two pieces of HVAC equipment that aren’t directly connected. For example, a jumper might connect an air handler to a furnace or a blower motor to an evaporator coil.
  • Jumpers attach two pieces of ductwork that are far from each other.
  • In some cases, jumpers may connect two HVAC systems: a forced-air system and a radiant heating system.

Regardless of their applications, jumper ducts ensure that HVAC systems function properly.

The Benefits of Installing Jumper Ducts in HVAC Systems

Jumper ducts have benefits that include:

  • Increased efficiency – Jumper ducts reduce airflow resistance. This allows for more efficient heating and cooling distribution throughout a home or building, resulting in lower utility bills.
  • Reduced noise – Jumpers can help reduce noise from an HVAC system. They do so by dampening sound waves when air moves from one piece of equipment to another.
  • Improved comfort – Jumpers ensure that air is distributed evenly throughout a home or building. This improves the comfort of its occupants.
a drawn diagram of the correct way to connect jumper ducts courtesy of the energy.gov website
Courtesy of Energy.gov. You can see the connection between two rooms via ductwork to increase airflow, total HVAC efficiency, and the other benefits of jumper (jump) ducts.

Why Jumper Ducts Are Efficient

According to the University of Florida, a typical duct system will lose up to 40 percent of its heating or cooling energy. The energy loss stems from the following:

  • Air leakage
  • Conduction
  • Convection

Jumper ducts help reduce these losses. In addition, jumper ducts:

  • Transfer heat energy from one area to another with minimal loss.
  • Allow for more precise control of the airflow in a system. This can help to improve the overall efficiency of the system.
  • Are made of a highly conductive material. That means heat energy is transferred quickly and efficiently.
  • Are insulated. This helps to further reduce heat loss.

How To Improve Jumper Duct Efficiency

Good jumper duct efficiency is key to maintaining a comfortable home. Unfortunately, issues that can thwart even the best ductwork include:

  • Thermal losses
  • Airflow losses
  • Airflow restrictions
A profession using a brush for air duct cleaning
Keeping your jumper duct filters clean will make the HVAC more efficient.

The best way to prevent these issues is to regularly clean and inspect your ductwork. Other ways to improve jumper efficiency are as follows:

  • Increase filter size
  • Clean and inspect ducts regularly
  •  Install air-balancing dampers
  • Utilize zoned heating and cooling systems
  • Choose better fittings
  • Use return filter grilles

Principles That Govern Effective HVAC Air Duct Design

There are five principles for designing an HVAC air duct system to ensure efficiency and effectiveness. Let’s review them.

Maintain Good Airflow

Too much airflow can lead to drafts and wasted energy, while too little airflow can make a room feel like a steamer.

The key is to find the right balance.

Keep the room at a comfortable temperature without wasting energy using manual dampers. These dampers allow you to change the airflow according to your needs.

Leave a Clear Path for Return Air

Leaving a clear path for return air ensures the system can circulate air effectively. This prevents hot or cold spots from forming.

Jumper ducts can keep air moving freely and prevent stagnation by removing obstacles. This can be especially important in areas where ventilation is crucial, such as a laboratory or hospital.

Properly Seal and Test for Leaks

Unsealed ductwork can lead to problems such as:

  • Reduced efficiency
  • Increased noise levels
  • Uneven temperatures

Leak testing is one of the best ways to seal the ductwork.

You have several ways to test for leaks, but the most common method is to use a smoke machine.

As its name implies, it pumps smoke into the ductwork system. If the smoke comes out of a certain place, that’s where leaks are most likely.

Use the Right Ductwork Material

Ductwork material also matters. Metal is sturdy and durable and can be easily shaped to fit any space. Fiberglass is also strong and pliable, making it ideal for a tight seal.

Both metal and fiberglass are non-porous. These materials won’t absorb moisture or promote mold growth. As a result, they are the only materials that can provide the quality and performance required for proper ductwork.

Use Proper Sizing

Using the correct size of ductwork is essential to ensure efficiency and effectiveness.

The size of a duct determines how much air can push through. If the duct is too small, the system won’t be able to circulate air properly.

If the duct is too large, air will be wasted, and energy bills will go up.

The best way to ensure you use the correct size ductwork is to consult an HVAC specialist. This way, you’ll be able to maximize the jumper duct’s functions.

Final Thoughts

A jumper duct is an integral part of an HVAC system. Following the principles of designing a jumper duct will ensure that they distribute air evenly throughout the home.

By allowing air to flow freely between the different system parts, jumper ducts can improve the system’s overall performance and reduce energy costs.


Apollo Home: 5 Principles That Make HVAC Air Duct Design Efficient and Effective | Attainable Home: Air Sealing HVAC Ducts Boots: How to Save Energy (12 Steps) |  Attainable Home: Ductless Mini-Split HVAC Noise Levels (Loud or Quite?) |  University of Florida: Energy Efficient Homes: The Duct System | Energy Vanguard: 17 Steps to Better Duct Systems | Jackson and Sons: Duct Efficiency Is Key for Running Your HVAC Unit

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