In a central HVAC system, ductwork plays a critical role in distributing conditioned air throughout the home. But when those ducts develop leaks, you’re not just losing airflow—you’re losing money and comfort. In fact, the EPA estimates that 20 to 30% of the air moving through a duct system can be lost due to leaks, holes, and poorly connected ducts. In this blog, we’ll walk you through why duct leaks matter, how to spot them, what to do about them, and when it’s time to call in the professionals.
Why Duct Leaks Are a Big Deal
Leaky ducts may not sound urgent, but they can have a major impact on your energy use and indoor comfort. When heated or cooled air escapes before reaching your living space, your HVAC system has to work harder—leading to higher energy bills, wasted money, and system strain. The problem is often hidden—since many ducts are located in unconditioned areas like attics, basements, or garages, leaks can go undetected for years. And it’s not just about comfort or cost—those gaps can pull in dust, mold, and other airborne pollutants, compromising your indoor air quality.
Common Signs Your Ducts May Be Leaking
Duct leaks can be sneaky, but there are several telltale signs to watch for:
- Higher energy bills: If your energy bills went up but your usage didn’t, this point to air escaping from the system.
- Inconsistent room temperatures: Do some rooms always feel too hot or too cold? The heated or cooled air could be escaping before it gets to them.
- Visible duct issues: Disconnections, kinks, or crushed sections can all indicate airflow problems.
- Ducts running through unconditioned spaces: Ductwork in attics or crawlspaces are more prone to leaks and energy loss.
- Dust and/or mold: Dust buildup, musty odors, or signs of mold could be caused by contaminants entering through leaky ducts.
How to Inspect Your Ducts for Leaks
Think your ducts might be leaking? A simple inspection can reveal a lot.
- Turn on your HVAC system so the air is actively moving through the ducts.
- Start by checking accessible areas, such as attics, crawlspaces, basements, or utility rooms.
- Use a smoke stick, incense, or even a small piece of toilet paper to test joints and seams. If the smoke or paper wavers or is pulled into a gap, you’ve likely found a leak.
- Mark any suspicious areas with a pencil or piece of painter’s tape so you can come back to them later.
Note: Be careful when inspecting attic spaces—always step only on joists to avoid damaging the ceiling below.
Simple DIY Air Pressure Test
Here’s a quick and easy way to check for potential duct leakage: open a window or door slightly and switch your HVAC fan on. If air seems to rush inward from outside, your home could be depressurized. That pressure imbalance might be caused by duct leaks allowing too much air to escape.
Can You Fix It Yourself?
Minor duct leaks can be sealed with mastic sealant or UL-listed foil tape—both are far better choices than standard duct tape, which tends to dry out, crack, and fail over time. DIY fixes may help with accessible sections of ductwork, but for more extensive systems or hidden duct runs, professional service is a smarter (and safer) bet.
The Benefits of Professional Duct Sealing & Insulation
Professional air duct sealing comes with major advantages. Sealed ducts keep your conditioned air where it belongs—inside your living space—not leaking into an attic or crawlspace. That means better indoor air quality, reduced dust and allergens, and improved health for everyone in the home. Proper sealing can also reduce energy costs by up to 20% or more. AIS technicians use durable materials like mastic sealant, R-6 or higher insulation, and mechanical fasteners for long-term results.
What a Properly Sealed Duct System Looks Like
When ducts are sealed and insulated correctly, you’ll notice a few key signs:
- No exposed sheet metal or asbestos insulation
- Secure straps every four feet to prevent sagging
- Joints that are sealed tightly with mastic or foil tape and screws.
- Filters don’t get dirty more quickly than expected
- Tight-fitting return grilles
- No black smudges or stains on insulation
When to Schedule a Duct Inspection
It’s time for a duct inspection if it’s been more than five years since your last one—especially if your home was built before 2005, when stricter duct sealing codes went into effect. Seasonal checkups are also a smart move before summer heat or winter cold puts extra strain on your system.
Choose AIS Heating & Air Conditioning for Your Duct Services
Leaking ducts don’t just hurt your comfort—they drain your wallet and lower your home’s air quality. Whether you’re unsure about your ductwork or know it’s time for sealing or ductwork repair, the experts at AIS Heating & Air Conditioning are here to help with comprehensive ductwork services. As a family-owned, Diamond Certified company with certified technicians, we’re proud to offer expert services backed by upfront pricing and trusted expertise.
Contact our team to learn more about AIS Heating & Air Conditioning’s duct sealing and insulation services today!
