What Most Homeowners Don’t Know About Their Ductwork
Your ductwork is the delivery system for everything your HVAC system produces — conditioned air. But it’s also the most overlooked component of the system. Ducts hidden in attics, crawlspaces, and wall cavities go years or decades without inspection, and problems accumulate invisibly while you pay the price in higher energy bills, uneven temperatures, and excess strain on your equipment.
Studies from the Lawrence Berkeley National Laboratory found that the average American home loses 20-30% of conditioned air through duct leaks alone. In Minnesota homes with ductwork running through hot attics in summer, those losses can be even higher — you’re paying to cool air that never reaches your living space.
Signs Your Ducts Are Leaking or Damaged
The most common symptom of duct problems is uneven temperatures throughout the house. Rooms far from the air handler that are always harder to cool in summer or heat in winter often indicate that conditioned air is leaking before it reaches those rooms. High energy bills with no obvious explanation are another indicator.
Visible signs include disconnected duct sections (sometimes visible in accessible attics or crawlspaces), flexible ductwork that has kinked, crushed, or sagged over time (flex duct supports degrade and collapse over years), and return air ducts that draw from unconditioned spaces — pulling hot attic air or cold crawlspace air into your system and forcing it to condition outdoor temperatures before delivery.
Duct Sealing vs. Duct Cleaning: What’s the Difference?
These are two different services that address different problems and are often confused. Duct sealing addresses leaks — gaps at connections, poorly taped joints, and deteriorated mastic sealant that allow conditioned air to escape into unconditioned spaces before it reaches your rooms. Sealing is done with mastic compound (a thick, brushable sealant) or high-quality metal tape applied to joints and connections. This is one of the highest-ROI improvements for most homes with older ductwork.
Duct cleaning addresses contamination — built-up dust, debris, mold, or pest waste inside the duct interior. This service is beneficial in specific situations: after construction or major renovation, if there’s visible mold growth in ducts, after a pest infestation, or if ducts haven’t been cleaned in 15-20 years and airborne debris is a concern. For most homes without these specific issues, duct cleaning isn’t necessary annually and should be evaluated based on actual conditions rather than marketed on a schedule.
When to Consider Duct Replacement
Ductwork in Minnesota homes built before the 1990s was often installed with less attention to sealing and may use materials that have degraded over the decades. Flex duct has a functional lifespan of roughly 15-25 years depending on installation quality and environmental conditions. Sheet metal ductwork can last indefinitely if properly maintained, but older systems often have undersized returns, poor layout, or pressure balancing issues that no amount of sealing and cleaning will fix.
If you’re replacing your HVAC equipment and your ducts are showing multiple issues, a duct system assessment alongside the equipment replacement can catch problems that would otherwise undermine your new system’s efficiency and comfort performance.
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Get a Duct Assessment
Advantage Air Plumbing, Heating & Cooling can inspect, seal, and service your ductwork to ensure your HVAC system is delivering what you’re paying for. Contact us today to schedule a duct assessment.
