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5 Signs You Have Leaky Ductwork in Your Denver Home

Leaky ducts waste 20-30% of your HVAC. Here are 5 signs your ductwork needs attention.

By On Time Heat & Air · April 2026 · Denver Metro

How do I know if my ducts are leaking?

The biggest telltale signs are rooms that never reach the thermostat temperature, excessive dust on furniture, higher energy bills without explanation, and whistling or rattling sounds from the vents. If your second floor is always hot in summer and cold in winter, leaky ductwork in the attic is a likely culprit.

How much does duct sealing cost?

Professional duct sealing in Denver runs $200-$800 depending on accessibility and the number of leaks. This typically pays for itself within one heating/cooling season through lower energy bills. We use mastic sealant and metal tape — never cloth duct tape, which fails within a year.

Can I seal my own ducts?

You can seal accessible joints with mastic sealant from a hardware store, but most duct leaks are in hard-to-reach areas — inside walls, above ceilings, and in crawl spaces. Professional duct sealing includes a blower door test to measure leakage before and after, so you know exactly how much improvement you got.

📋 The Bottom Line

If you're dealing with this issue in the Denver Metro area, the most important thing is getting a proper diagnosis from a NATE-certified technician who understands Colorado's altitude. At 5,000+ feet, HVAC systems behave differently than at sea level — refrigerant pressures, combustion efficiency, and airflow all change with elevation. A technician who doesn't account for altitude can misdiagnose the problem entirely. On Time Heat & Air has been serving the Front Range since 2013 with same-day service, upfront pricing, and no overtime fees for emergency calls. Call (720) 527-0668 for a diagnosis.

Why This Matters for Denver Homeowners

Colorado's climate creates unique HVAC challenges that homeowners in other states don't face. Our dry air, intense UV exposure, extreme temperature swings (it's not unusual to see 60°F days followed by 20°F nights), and hail storms all take a toll on heating and cooling equipment. Systems here work harder and fail in different ways than identical systems at sea level.

Brighton, where we're based, sits at 4,984 feet. Denver is at 5,280 feet. Aurora, Lakewood, Arvada, Westminster — they're all above 5,000 feet. That altitude affects everything from gas pressure in your furnace to refrigerant charge in your AC to the amount of air your blower motor needs to move. Every system we install or repair is calibrated specifically for Front Range conditions.

We're licensed in 8 Colorado counties with active, verifiable license numbers displayed on our website. Our technicians are NATE certified — the highest certification in the HVAC industry. And we've maintained a 5.0 Google rating across 70+ reviews because we show up on time, diagnose honestly, price upfront, and fix it right the first time.

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