DUCT SEALING PROS · SYMPTOMS
Signs of Leaky Ducts in a St. George Home and What to Do About Them
The signs of leaky ducts are easy to notice and easy to blame on something else: a room that never cools, an air conditioner that never stops, weak or noisy airflow, dust around vents, hot spots and damp insulation. A pressure test confirms whether ducts are the cause.
Six signs of leaky ducts to look for
Leaky ducts rarely announce themselves. You notice the symptoms instead. These six signs of leaky ducts are the ones St. George homeowners describe most often, and each has its own page with causes and next steps.
| Sign | What you notice | Read more |
|---|---|---|
| Rooms that never cool | One room, usually upstairs or at the far end of the house, never catches up on a 105°F afternoon | Rooms that never cool |
| Nonstop AC and high bills | An AC that runs almost nonstop from June through September, with bills to match | High AC bills |
| Weak or noisy airflow | Weak airflow at some registers and a whistle or rattle at others | Weak or noisy airflow |
| Dust around vents | Fine red dust building up around vents and on nearby furniture | Dust around vents |
| Hot spots | Rooms over the garage or at the end of a long duct run that run hot | Duct leakage test |
| Damp or damaged ducts | A musty smell or damp insulation near the air handler, or torn duct | Damp or moldy ducts |
Why these signs of leaky ducts appear together
When ducts leak, cooled air escapes into the attic before it reaches the rooms. The air conditioner has to run longer to make up for the loss, and rooms at the end of the duct run get the least air. Return leaks can also pull dusty attic air into the house, which is where the dust around vents comes from.
Attic air can reach 120°F or higher on a sunny summer day, so every leak sends cool air into an oven. Our guide to why ducts leak here explains how the climate and the construction work against ducts.
How to tell if ducts are the cause
Symptoms alone cannot tell you. Rooms run hot for many reasons, including window exposure, insulation and equipment size. The only way to know whether the signs of leaky ducts in your home point to leakage is to measure it.
- Note which rooms run hot or cold and at what time of day.
- Look at your summer bills for a pattern.
- Book a duct leakage test to get a leakage number.
- Compare the options in our guide to sealing versus replacing ducts.
If the test shows your ducts are tight, we will say so and you keep your money.
What to do next
If you recognize two or more of these signs of leaky ducts, a test is the next step. A typical sealing job, if the test justifies one, runs 2 to 8 hours, and about 4 hours for most homes, according to Angi. See our duct sealing cost guide for what to expect, and our overview of duct sealing methods for how each job works.
The sooner you check, the more choice you have about timing. HVAC service calls can take 24 to 48 hours in the hottest weeks, and a duct test is easier to schedule in spring or fall.
Frequently asked questions
What are the most common signs of leaky ducts?
Rooms that never cool, an air conditioner that runs almost nonstop, weak or noisy airflow, dust around vents, hot spots and damp or damaged ducts.
Can leaky ducts raise my bill?
Yes. When cooled air escapes before reaching the rooms, the air conditioner runs longer to make up for it.
Do all signs of leaky ducts mean I need sealing?
No. Other causes can look the same. A pressure test tells you whether leakage is behind the symptoms.
Where do I start?
Book a duct leakage test. It gives you a baseline number and tells you what to do next.
Ready to find out where your cool air is going?
Call us and tell us which rooms are giving you trouble. We will explain what a duct leakage test involves and book your duct sealing services St George crews can finish before the next heat wave.
Duct Sealing Pros
3430 S River Rd, St. George, UT 84790
(435) 281-0395