If you hear any What is the Scratching Sound Coming from the Air Vent sounds coming from your air vents, it’s important to address the problem as soon as possible. Ignoring these sounds can cause serious damage to your HVAC system and increase energy bills. Strange sounds from your vents could also indicate a safety issue and may be an indication of rodents nesting inside your ductwork. This article explains the most common reasons your air vents are making weird noises and what to do about it.

Scratching Sounds

Rattling, scraping or scratching sounds are caused by loose metal parts knocking against each other inside your air ducts. This can happen when a duct is not properly sealed, or as the seals age over time. It can also occur when a ductwork component, such as an electric actuator, isn’t properly secured or grounded. This issue will get worse over time, so it is important to call a professional right away.

Decoding the Mystery: Unraveling the Reasons Behind Scratching Sounds in Your Air Vents

Other sounds, such as a loud hum, screeching or squealing, can be a sign that your air conditioner motor is worn out or that the blower is unbalanced. These sounds usually occur in short bursts. They can also be caused by heat- or cold-related duct expansion or contraction, or by changes in duct pressure. Narrow ducts are more prone to these problems than wider ducts.

If the sound is a constant scratching noise and is occurring throughout the house, you likely have mice in your air ducts. You can confirm this by listening for scurrying sounds in the early morning or at bedtime, or taking a visual examination of your attic or walls for droppings.