do I need new ducts

Do I Need New Ductwork With a System Replacement?

Byaviator

When it’s time to replace your air conditioner or furnace, there’s often one big question homeowners forget to ask: Do I need to replace my ductwork too? While it might seem like your existing duct system can be reused, the truth is—outdated, damaged, or poorly designed ducts can severely limit the performance of your new HVAC system.

In this post, we’ll walk through when new ductwork is necessary, how to tell if your current setup is holding you back, and what to expect from a properly designed system.

Why ductwork matters during an HVAC upgrade

When replacing your HVAC system, it’s easy to focus solely on the furnace or air conditioner. But the truth is, your ductwork plays an equally important role in your home’s overall comfort, efficiency, and system performance.

Think of your ductwork as the lungs of your HVAC system—carrying conditioned air from the equipment to each room and returning air back to be heated or cooled again. If your ducts are undersized, leaky, damaged, or poorly designed, even the most advanced HVAC unit can struggle to do its job.

Here’s what can happen when ductwork isn’t up to par:

    • Uneven temperatures between rooms
      Some areas stay too warm, others remain too cold—usually because airflow isn’t balanced or the ductwork layout doesn’t match your home’s current needs.
    • Weak airflow and poor system performance
      Undersized or obstructed ducts restrict air movement, causing longer run times and inadequate heating or cooling.
    • Increased wear and tear on HVAC components
      When your system has to work harder to push air through inefficient ducts, it puts stress on the blower motor, compressor, and other parts—leading to premature breakdowns.
    • Higher utility bills
      Leaky or poorly insulated ducts allow conditioned air to escape into walls, attics, or crawlspaces—wasting energy and driving up monthly costs.
    • Excess noise
      Whistling, rattling, or banging sounds may indicate airflow problems, high static pressure, or loose duct connections.
    • Humidity and air quality issues
      If ducts are drawing in unfiltered air from unconditioned areas, you might experience higher indoor humidity or increased dust and allergens.

Why timing matters

Replacing your HVAC system is the ideal time to assess your ductwork. Your new equipment will likely be more efficient and use different airflow standards—so your old duct system might not be compatible. Rather than installing a top-of-the-line unit into a flawed delivery system, it’s smarter to evaluate both together.

Aviator Heating & Cooling can help ensure your ducts are the right size, layout, and condition to support your new system—giving you better comfort, lower energy bills, and fewer headaches down the road.

Signs your ductwork may need to be replaced

Even if your HVAC equipment is working well, aging or damaged ductwork can quietly undermine your comfort and efficiency. If you're planning a system replacement or even if you’re just noticing performance issues it’s worth considering whether your ducts are part of the problem.

Here are the most common signs your ductwork may need to be repaired or replaced:

1. Age and visible deterioration

Most ductwork isn’t built to last forever. If your ducts are 15–20 years old or more, they may already be compromising your system’s performance.

      • Metal ducts can rust or separate at the seams over time.
      • Fiberglass-lined or flexible ducts may sag, collapse, or lose insulation value.
      • Older ducts are often sealed with outdated materials like duct tape that degrade over time, causing leaks.
      • Ductwork standards have improved—what was once acceptable may now be inefficient or poorly sized.

What to check:
If you can access your ducts in a crawlspace, attic, or basement, look for rust, sagging, disconnected joints, or torn insulation.

2. Uneven heating or cooling

Consistent hot or cold spots in your home often point to airflow problems. In many cases, that comes down to the ductwork.

      • Duct runs may be too long, too narrow, or routed inefficiently.
      • Registers may be incorrectly placed, especially in home additions or remodeled areas.
      • Leaks or crushed sections of duct can restrict airflow to certain rooms.

What to watch for:

      • One room always feels colder or hotter than the rest
      • Your thermostat doesn’t match how the space feels
      • You’re constantly adjusting vents to try to “balance” the airflow

3. High energy bills

When your HVAC system has to work harder to push air through leaky or poorly designed ducts, it uses more energy—plain and simple.

      • Studies show that leaky ducts can waste up to 30% of conditioned air.
      • The system runs longer to achieve the set temperature.
      • Poor duct insulation allows cooled or heated air to lose its temperature before reaching your living space.

Tip:
Compare your current energy bills to previous years or your neighbors’ usage. A steady rise with no clear reason may point to duct inefficiency.

4. Dusty or poor indoor air quality

If you’re noticing more dust in your home—or allergy symptoms are worse indoors—your ductwork could be the culprit.

      • Gaps in duct seams can pull in attic dust, insulation particles, or even mold spores.
      • Lack of proper filtration or sealing lets pollutants circulate through your system.

Symptoms of duct-related air quality problems:

      • Dust buildup on furniture shortly after cleaning
      • Musty smells when the system runs
      • Aggravated allergy or asthma symptoms indoors

5. Noise from the ductwork

Your ductwork should operate quietly in the background. If you're hearing strange sounds, it could indicate that something isn’t right.

      • Whistling: Often caused by air escaping through small leaks or cracks
      • Banging or popping: Usually occurs when undersized ducts expand or contract with air pressure changes
      • Rattling: Loose connections or improperly secured duct segments

Bottom line:
Noisy ducts aren’t just annoying—they can signal airflow restrictions, structural issues, or potential air leaks that waste energy and reduce comfort.

When replacing your HVAC system, it’s the ideal time to correct these duct issues before they lead to bigger problems. The team at Aviator Heating & Cooling can inspect your ducts and recommend whether a simple fix or a full replacement will give you the best results for comfort and efficiency.

When existing ductwork can be reused

Not all duct systems need to be replaced during an HVAC upgrade. In many cases, if your current ductwork is in good shape and was properly designed for your home’s size and layout, it can continue to serve your new equipment well. Recognizing when a duct system is still viable can help you save money while still optimizing comfort and efficiency.

Here are some key factors that suggest your ductwork may be reusable:

Strong and balanced airflow throughout your home

If every room receives a steady, even supply of air—and you’re not dealing with hot or cold spots—that’s a good sign the duct layout is efficient and functioning properly.

    • No major pressure imbalances
    • Return air and supply air are well-distributed
    • Each space reaches and maintains the thermostat setting without issue

Ducts have been regularly maintained and inspected

Ongoing maintenance plays a major role in the longevity of your ductwork. If your ducts have been cleaned, sealed, and checked as part of routine HVAC service, they’re less likely to have hidden issues.

    • No visible dust buildup or contamination
    • Joints remain sealed and secured
    • Insulation is intact and undamaged

No evidence of damage or air leaks

If your ductwork isn’t leaking conditioned air into unconditioned spaces (like attics or crawlspaces), and the materials show no signs of deterioration, you may not need to replace it.

    • No holes, cracks, or loose fittings
    • Metal ducts show no rust or corrosion
    • Flexible ducts are not kinked, sagging, or torn

Duct layout and sizing match your new system’s requirements

Even if your ducts are in decent physical condition, they need to be appropriately sized for your new system to avoid airflow problems. When ductwork was originally designed with your home’s square footage and load requirements in mind—and aligns with your replacement equipment—it can often be reused with confidence.

    • Duct sizing supports proper static pressure
    • Supply and return runs are proportionate to equipment airflow
    • Zones and dampers are compatible with system design

Even if your ducts meet all the above criteria, professional evaluation is still essential during a system replacement. Minor upgrades—such as sealing joints, replacing insulation, or rebalancing airflow—can dramatically improve comfort and energy efficiency. At Aviator Heating & Cooling, we always perform a full duct inspection before installing any new HVAC system, so you can rest assured that every part of your system is optimized for peak performance.

Benefits of upgrading your ductwork with your HVAC system

If your ductwork is failing, upgrading it along with your new furnace or AC offers several long-term benefits:

    • Maximized system efficiency — Your equipment won’t have to overcompensate for airflow losses
    • Improved comfort — More even temperatures and faster heating/cooling cycles
    • Lower energy bills — Less wasted air and reduced runtime
    • Quieter operation — No more whistling or banging from undersized ducts
    • Longer system lifespan — Reduced strain on components like the blower motor and compressor

What a proper duct redesign looks like

If your ductwork needs replacement, Aviator Heating & Cooling will start with a complete evaluation of your home. We’ll perform:

    • Load calculations to determine the right system size
    • Duct sizing and layout to ensure balanced airflow
    • Duct sealing and insulation to improve energy efficiency
    • Installation of new registers or grilles if needed

Our goal is to give you a total HVAC solution—not just swap out the equipment.

Proudly serving Hillsboro and surrounding areas

We provide expert HVAC system replacements and ductwork upgrades across:

No matter where you’re located in the Portland metro area, we’re here to help you get the most out of your HVAC investment.

Ready to improve your comfort and efficiency?

Let’s make sure your new system is set up for success.
If you’re replacing your furnace or AC, now is the ideal time to evaluate your ductwork. Aviator Heating & Cooling offers honest assessments, expert recommendations, and professional duct upgrades to maximize your comfort and savings.

Call us today or request an estimate online to get started—we proudly serve homeowners throughout Hillsboro and the surrounding Oregon communities.

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