Can I Use My Existing Ductwork for a New HVAC Installation?

Every home with an HVAC system installed relies on ductwork to transport cool or warm air. When an HVAC system is installed, the existing ductwork is often kept. When faced with this scenario, homeowners must consider if their ductwork should be retained or replaced.

Our certified heating, ventilation, and air conditioning technicians have years of experience installing and servicing ductwork in hundreds of homes across Los Angeles and surrounding cities. At Monkey Wrench Plumbing, Heating & Air, we’ve seen ductwork in all sorts of conditions and have advised homeowners when it’s necessary to replace current ductwork or use the existing system.

If the existing ductwork is well-maintained and sized, in newer condition, and in an ideal location throughout the home, it may be suitable for a new HVAC installation. On the other hand, if the current ductwork is old, in bad shape, or incompatible with a new HVAC system setup, then replacing the ductwork may be required.

In this article, we’ll review each factor so that every homeowner knows whether or not their home’s existing ductwork is suitable for a new HVAC installation.

Let’s get started!

Circumstances Where It’s Okay to Use Existing Ductwork

Homes with HVAC systems can use their existing ductwork when it’s time to replace their heating or cooling systems. In general, newer homes built or refurbished within the last 20 years have a higher chance of using the current ductwork for a new HVAC system.

When unsure if their home’s ductwork can be used for a new HVAC installation, here’s what homeowners should consider.

Well-maintained Ducts

If ductwork is maintained properly, it is more likely to be kept and used for a new HVAC installation. Well-maintained ductwork can be considered for a new HVAC installation if it has no leaks, deterioration, or damage.

Homeowners can ensure they have their ductwork maintained by having annual inspections. During these HVAC tune-ups, technicians can perform maintenance checks such as checking duct joints, the insulation condition, and the ductwork’s static pressure. If the return and supply ducts have been taken care of, an HVAC installer may recommend duct cleaning to prepare the existing ductwork for a new installation.

A well-taken care of ductwork will help any new HVAC installation maintain its heating and cooling efficiency. If the ductwork is recent, then chances are it’s in excellent condition to support a new HVAC installation.

Newer Ducts

New and recently installed ductwork is far more likely to support a new HVAC installation than older ducts. There isn’t a set age for when ductwork can be considered new or old, but the more recent it is, the better.

Brand-new ductwork is less likely to have problems and is usually in amazing condition. This makes it an ideal candidate for keeping when a furnace or air conditioner needs to be replaced.

A technician will be more than willing to use existing ductwork for a new HVAC system if the ducts are new and may only need to make minor adjustments to ensure it connects with new HVAC systems. Sometimes, the only minor adjustment needed to alter the location of the ductwork with the new HVAC unit.

Location and Sizing of Ductwork

It’s vital to consider the overall duct layout and design when deciding if the existing ductwork should be kept for a new HVAC system. An ideal duct system doesn’t have too many bends and corners since it can affect the airflow. Over- or undersized ducts can negatively impact the airflow from a new HVAC unit and affect the system’s efficiency.

HVAC technicians rely on an air duct calculator to determine the proper design layout for ductwork. If the air duct calculator determines that the current location of the ductwork meets the duct requirements from a new HVAC system, it can be kept.

Well-located and adequately sized ducts are great candidates to keep for a new HVAC installation, but there are more instances where it’s best to consider replacing them instead.

Scenarios Where Existing Ductwork Is Not Okay for New Installation

Most of the time, when a new HVAC system is being installed, there’s a higher probability that it will need to be replaced instead of kept. Even if the existing ductwork is deemed okay for a new installation, it may run into problems in the future.

Here are some significant factors that help determine when a current duct system needs to be replaced to complement an HVAC installation better.

Old Ductwork

Outdated ducts should be replaced instead of kept because they can break down after installing a new HVAC unit. Old ductwork can also obstruct an HVAC system’s ability to heat or cool.

Ducts can last around 30 years, but it’s recommended to consider replacing it after 20 years. After years and years of use, ducts made out of certain materials, such as fiberglass and metal, can rust and deteriorate. Old ductwork is also highly likely to be in poor working conditions.

Ductwork in Poor Condition

Whether it’s new or old, if the existing ductwork is in bad condition, it will not be suitable for a new HVAC installation. Here are some examples of ducts considered to be in bad condition.

• Leaks or cracks that cause loss of air
• Insufficient insulation that affects the heating and cooling efficiency of the HVAC system
• Present mold or Asbestos poses health risks

There may be an opportunity where an HVAC technician can repair ductwork in bad condition, but replacing the entire duct is usually recommended. In some cases, ducts can be in decent condition and operating fine but not adequately sized to support a new HVAC system.

Current Ductwork Not Compatible

If the existing ductwork doesn’t meet the design and load requirements for a new HVAC system, it must be replaced. HVAC technicians look at a home’s number of rooms and overall square footage to determine ductwork sizing requirements.

These calculations are also considered when an HVAC technician determines if the current ductwork can be used for a new system install. If the wrong-sized ductwork is kept for a new installation, the HVAC unit may experience inefficient heating or cooling issues.

Should I Replace or Use the Current Existing Ductwork?

There are several factors to consider when deciding if your home’s current ductwork can be kept for installation. Now that you know what these factors are, you can move forward with a new HVAC installation that includes new ductwork.

At Monkey Wrench Plumbing, Heating & Air, our technicians are servicing ductwork on a weekly basis. We’ve seen ductwork in all conditions and replaced bad ducts in hundreds of homes across Los Angeles.

If you’re interested in a ductwork inspection, contact us using one of the buttons below. You can also book an appointment with a certified HVAC technician through our HVAC online scheduler.

If you’re considering a new HVAC installation, consider learning how to make your new system more efficient.