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Noise Control: HVAC Repair for a Loud HVAC System

By Your Comfort Advisor 6/27/16 9:00 AM Time to read:

 Modern air conditioning units are quieter than ever. Technological advancements have made it possible to reduce their operating noise so homeowners can enjoy a comfortable home without the nuisance. Sometimes, however, abnormal noises do come up. Since there are many complex parts working together, it is often difficult to diagnose the issue. There could be a variety of possible causes but some are more common than others.

Why So Loud?

In order to determine the cause of the overbearing noise, homeowners must first locate the source of the irritating sound and then determine what type of sound it is. Before checking internal components of their air conditioning unit, however, homeowners should turn off their HVAC system along with the thermostat.

Fan Motor Squeaks: Fan motor squeaking requires an internal inspection of the unit. Sometimes, the squeaking could be due to a dirty fan blade that has been dented. When dirt accumulates on a fan blade it causes it to become imbalanced and eventually noisy. A bent or imbalanced fan blade can scrape the unit's casing. A badly damaged blade will need replacement. If the fan does not move smoothly, the center bolt will need to be tightened. If none of these tips help, the squeaky noise could likely be the result of a bearing that needs lubrication.

Noisy Air Conditioner: Rattling noises coming from a unit usually means there is something loose. When it comes to working on HVAC units, it helps to work from the inside out, especially when tightening the air conditioning unit's panels.

Rattling Ducts: Rattling ducts require homeowners to check all the ducts for loose joints. This may require them to go into their attic to inspect by walking on support joists. If any joists are loose, homeowners should tighten them with duct screws and use HVAC tape, if necessary. If rattling continues, homeowners may need to hire an HVAC professional to inspect their HVAC system.

Determine the Type of Sound

The type of sound an air conditioner makes coincides with the type of damage (if any). To diagnose the problem, homeowners must first determine where the noise is coming from. Once located, they should decipher what type of noise it is. Sometimes, however, only an experienced HVAC technician can make this determination. For homeowners who want to proceed, here's a short guide on different HVAC sounds.

  • Mild squeaking from air conditioner: A squeak usually means a bearing is in need of lubrication or a fan blade is out of balance due to it being dirty.
  • Rattling from air conditioner or ducts: Rattling typically means there is a loose panel or duct in need of tightening.
  • Grinding noise: A good rule of thumb is the harsher the noise the more serious the problem. Grinding noises could imply a bearing is going to fail and needs immediate replacement.
  • Hissing sounds: A hiss is the sound that should cause the most concern. If the source is the air conditioner, it could indicate a freon leak. It could also be due to loose ductwork, a less serious cause.

Sometimes homeowners can diagnose and fix a loud air conditioner by themselves. Other times, however, the cause is too complex and requires the assistance of a professional HVAC technician. For those situations, we're here to help.