What These 8 HVAC Noises Are Trying to Tell You

Ever wake up in the middle of your nap because of an odd noise from your beloved AC unit? Well, this could definitely be troublesome, especially if the issue has been around for quite some time already.

If your AC unit is experiencing some problems, don’t hesitate to reach out to a professional like American Home Water and Air for AC repair in Phoenix.

Common HVAC Noises to Take into Account 

To ease your burden, it’s important to be knowledgeable of the common HVAC noises. Check out the list below and be adept beforehand so you can make the best decision when you encounter these issues in the future.

1. Grinding or rattling

When dirt and debris make their way into the air filter and enter the system, this can cause grinding noises. Having these particles inside the unit can severely affect the working condition of the HVAC system. The small debris may cause friction between mechanical components and if not repaired quickly, it may damage key components, resulting in a possible breakdown. 

Rattling sounds may also be influenced by a damaged motor, loose fan blade, or detached panels. Either way, it’s important to consult an HVAC technician as soon as possible to identify the major source of the noise.

2. Screeching or squealing

This type of sound is often associated with a damaged fan belt. A fan belt is an essential component of a unit as it transfers rotational power from one part to another. Therefore, if there’s something wrong with this pivotal component, it should be fixed immediately. Once checked, experts will advise whether to ultimately replace the fan belt or just add lubricant to eliminate the noises. 

The lubricant added, however, is not something readily available at the hardware stores. It is a special lubricant type that only HVAC experts can handle. Personally adding this lubricant to the fan belt may be difficult as there are different furnace types and models.

3. Clanking or banging

On the other hand, if the noises appear to be banging, the issue could be a loose part or a broken component in the HVAC system. If the clanking is very loud, this could be a more serious situation. If the banging noise is not inside the system but rather outside, the issue may be related to a damaged outdoor fan or outside compressor. Meanwhile, the problem could also be associated with air ducts because of debris from animals or a storm. 

If you are unsure of the cause or if the sound is continuous, make sure to turn off your unit immediately and contact your HVAC technician. This particular noise can signify a greater problem, hence needed to be addressed immediately.

4. Hissing

A leak in the air duct produces a hissing sound from the system. It can occur if the air filter is not properly set, or perhaps it’s not the correct size for your unit. Other possible reasons are refrigerant leak and malfunctioning valve. 

If the sound appears to be a high-pitched hissing, turn off the unit instantly. There could be high pressure on the compressor, causing unwanted noise. If neglected, it may cause an explosion because of the building up of pressure in the HVAC system. Therefore, you need to take this as a warning sign and seek professional help as soon as possible.

5. Bubbling or gurgling

Gurgling noise from your unit is often caused by problems with the drainage line. The sound arises because there is a crack or blockage on the pipe. Because of the damaged pipes, it traps air within lines navigated by the liquid coolant or also called the refrigerant. While you may repair the affected pipe on your own, it’s advisable to get help from an HVAC specialist as the issue can be crucial.

In addition, working with refrigerants can be risky for both your health and even the environment. This chemical compound generally cuts off the oxygen supply, hence highly toxic and flammable.

6. Thwapping or slapping

Sounds that seem like slapping is normally linked with the blower’s fan blades. The source of this noise could be that something is stuck on the blades, disrupting the airflow and creating a thwap-like sound. If the debris remains within the fan blades’ area, this may not be a very critical issue.

However, if the particle enters the system, this creates a more serious problem because it damages other internal components. Additionally, the frequent slapping sounds may result in wear and tear of parts, or worse premature replacement of your unit.

7. Popping

Evaluating the popping sounds can be tricky. If the source of noise is from the ductwork, then it is considered a common HVAC noise, especially if the HVAC system has not been turned on for quite a while. The sound is a result of cold metals ducts preparing to work and expanding because of the gust of warm air. Because it’s often a normal occurrence, the sound will eventually go away as the pressure inside the system subsides. 

Meanwhile, if the popping does not stop or the source noise is not from the ductwork, then it could be a major issue. Constant popping noises may stem from leaking or malfunctioning air ducts, hence an expert’s guidance is a must.

8. Buzzing

Several factors can cause a loud buzzing vibration in the HVAC system. One of the most common reasons is because of a loose fan motor. It could also be a defective air filter, loose fan blade, or dirty air filter. 

On the other hand, major issues like a refrigerant leak, copper line obstruction, and debris interference inside the unit could stir up the buzzing noise. Whatever it is, this can be a sign of a serious issue in your unit. So, it is recommended to consult your HVAC technician to make a sound diagnosis of the problem. 

Tips on How to Prevent a Noisy HVAC System

Noises are generally linked with run-down units with no regular tune-ups. Therefore, maintaining your HVAC system in tiptop condition is crucial for your unit’s health. Don’t miss any scheduled maintenance and always keep your HVAC equipment clean. And of course, you can get help by inviting technicians to solve all your HVAC issues.