What Is Duct Sealing?

Tucked away behind walls, under floors, or in attics and crawspaces, your home’s ductwork does its job quietly and consistently. But when issues like cracks, holes, or leaks develop, your air ducts start to make their presence known. From uneven room temperatures to higher energy bills, leaky ducts can cause more disruption than you might expect.

That’s where duct sealing comes in. Duct sealing is an effective solution that helps restore your HVAC system’s performance, efficiency, and comfort without the need for expensive repairs or replacement. Keep reading to learn how duct sealing works, why it matters, and signs it’s time to call in a professional.

What Are Ducts, Anyway?

Ducts are the pathways that carry heated or cooled air from your HVAC system to the rooms throughout your home. Think of them as the circulatory system for your indoor comfort. But when those ducts develop leaks or lose their tight connections, a significant portion of that conditioned air never reaches its destination.

In fact, according to ENERGY STAR, as much as 20-30% of the air moving through the average home’s duct system escapes through leaks. That’s air you’ve already paid to heat or cool – wasted in unused spaces such as attics, crawl spaces, or behind drywall.

Signs Your Ductwork Might Be Leaking

Since ducts are often hidden from view, it’s not always obvious when there’s a problem. Here are some telltale signs that your ductwork could be leaking:

• Uneven temperatures in different rooms
• High energy bills, even with regular HVAC maintenance
• Excess dust in your home, especially near vents
• HVAC system running more often or longer than usual
• Weak airflow coming from certain vents
• Rattling or whistling sounds when your system is on

If you’ve noticed one or more of these issues, leaky ductwork may be to blame.

How Duct Sealing Fixes the Problem

Duct sealing is the process of identifying and closing leaks, gaps, or loose connections in your duct system. Here’s a basic overview of how the duct sealing works:

1. Inspection: A professional HVAC technician inspects your duct system, often using tools like pressure gauges, smoke pencils, or thermal imaging to detect leaks.
2. Cleaning and Access: Technicians may need to clean the ducts or create small access points to reach hidden sections.
3. Sealing: Depending on the size and location of the leaks, they’ll use one or more of the following materials:
   • Mastic sealant: A thick, sticky substance applied over cracks or seams
   • Foil-backed tape: Special HVAC tape that resists heat and pressure (not to be confused with regular duct tape!)
   • Aerosol-based sealants: These are sprayed inside the duct system and automatically seal up leaks from the inside out

Once sealed, the technician will retest the system to ensure airflow and pressure are back to normal.

Benefits of Sealing Your Ducts

The advantages of duct sealing go beyond just patching up holes. Here’s what you can expect:

• Lower energy bills: Less air loss means your HVAC system doesn’t have to work as hard.
• Improved comfort: Say goodbye to hot or cold spots in your home.
• Longer HVAC system lifespan: Less wear and tear means fewer repairs and a system that lasts longer.
• Better indoor air quality: Sealed ducts reduce the amount of dust, allergens, and pollutants entering your system.
• Environmentally friendly: Using less energy helps reduce your home’s carbon footprint.

When to Repair, Replace, or Maintain Ducts

Sealing is a great solution, but it’s not always the answer for every duct problem. Here’s a general guide:

• Repair: Small leaks, minor damage, or loose joints can often be fixed with sealing or minor patching.
• Replace: If your ducts are more than 20 years old, severely damaged, or made of outdated materials, replacement may be the better option.
• Maintenance: Annual inspections and cleaning help prevent duct leaks from forming and catch issues early before they become expensive problems.

If you’re not sure what your system needs, a qualified HVAC technician can help you assess the condition of your ductwork and recommend the best course of action.