Residential and Commercial HVAC Houston

Why Does My AC Make Loud Noises?

Why Does My AC Make Loud Noises

In Texas, we rely on our air conditioners throughout the majority of the year. When there is a breakdown in the functionality of your AC, you will want to address it as soon as possible to avoid more expensive repair costs and breakdowns.

One of the warning signs that you have an issue with your air conditioning unit is unusual or new sounds coming from your air conditioner. These sounds may be banging noises, squealing noises, rattling noises, or some other uncommon sound. You will want to call a professional HVAC technician as soon as possible in order to have your system inspected before you have a breakdown leaving you without cool capabilities.

Without adequate cooling capabilities, you not only create an uncomfortable environment, but you also run the risk of damaging your property. Moisture and high temperatures can lead to conditions that warp wood and other housing materials, as well as increase the chances of mold and mildew development.

When you have a malfunctioning air conditioning system in your home, working with a professional HVAC company can help you to restore functionality and comfort in your space. Call Autumn Mechanical in Houston today for your urgent AC services in Spring, Texas.

Why Does My AC Make Loud Noises?

1. Squealing and Screeching

If you hear a squealing or screeching noise (think nails on a chalkboard or a fork scratching on a porcelain plate) coming from your air conditioner, it’s caused by moving parts in your AC unit wearing out and breaking. For example, the belt may need replacement. Or, the motor bearings may be damaged, which will cause the motor to be off-center—thus the screeching.

Repairing and replacing belts and motor bearings before they stop working altogether will prevent your HVAC from shutting down. Maintenance is the most important thing you can do to keep these parts in good shape.

Another reason these noises happen is that your motor needs lubrication. Make sure to use the correct type of oil (either a mineral or synthetic) if you choose to do this yourself. The oil you use shouldn’t have any detergent in it, and common oils used around the house, like WD-40, are too light for this issue.

2. Rattling

A rattling sound coming from your AC unit could mean:

  • A part has come loose: Turn off the power to your unit. This needs to be repaired by a pro before the part breaks or disconnects completely
  • The motor is damaged: If the motor appears to be damaged, leave it to a professional to replace it
  • The panels or doors are loose: Check if the panels and doors outside your unit are firmly attached. Tighten any loose screws
  • Debris is caught in your AC: There may be some twigs or other material caught in the mechanism

3. Thumping

It’s normal to hear a thumping noise when your air conditioner powers down, but continuous thumping means something is not working correctly.

Thumping can occur inside your house when the filter hits the return grille (the piece that covers the duct and filter) or when the blower fan has come loose. Thumping can also indicate a broken seal or hole in the ductwork.

If you hear thumping from outside, your compressor springs may be broken, or the fan is hitting metal. If you hear thumping repeatedly and it’s getting louder, it may be time to contact a local HVAC pro to take a look.

4. Thwapping

If you hear a “thwapping” sound, similar to playing cards on bicycle spokes, something may be stuck in the blower blades or touching the blower from inside the unit. This issue is not severe, but it could cause the belt or motor to wear out more quickly than it should.

5. Repeated Clicking

Repeated clicking can be caused by:

  • The relay process: A repetitive clicking noise in your HVAC means there’s a problem in the relay process in the thermostat that regulates the air temperature
  • An electrical problem: Clicking can indicate an electrical problem connected to the HVAC, which causes the relay to stop working properly
  • The contactor: The contactor, the connection between the thermostat and the compressor unit, may be damaged and need replacement

These problems should be fixed by a local professional technician.

6. Buzzing

If there is persistent buzzing coming from your outside HVAC unit, it’s a good indicator that there’s a refrigerant leak or that your unit is freezing up from too much usage. Turn off the air conditioner for a few hours and then start it up again. If this happens a lot, your unit needs repair.

Buzzing can also mean that your condenser fan is not working. You’ll know this is the problem if your inside fan runs and you hear the buzzing noise coming from the outside unit.

Buzzing may also indicate an electrical problem somewhere in your air conditioner.

7. Banging

When there’s a loud banging as your unit runs, it’s broken and needs repair. For example, you may have a damaged piston pin or connecting rod. Banging can also mean you need a compressor replacement. You should stop using the unit until it is repaired or replaced.

Air Conditioning Financing Options in Houston, TX

When your AC fails to control the climate of your space you can be left with a new set of issues, all the way from warped wood to mold, your issue can become expensive quickly. At Autumn Mechanical, we offer our clients financing options that help them get the services they need when they need them. Take advantage of special financing options available with approved credit when you purchase qualifying Trane equipment through Wells Fargo. Financing is provided with approved credit by Wells Fargo National Bank, an equal housing lender. If you have any questions about the financing options we off

Affordable HVAC Services Near Me

Autumn Mechanical — formerly Autumn Air delivers a single-point resource for mechanical contracting and service. Based in Spring, TX, Autumn Mechanical specializes in HVAC, plumbing, and refrigeration services. Serving customers in Houston, Dallas, and surrounding areas, our professional technicians serve with expertise and integrity.

With over 30 years of experience in the air conditioning and heating business, the team at Autumn Mechanical has built a trusted reputation throughout the communities of Houston. Our air conditioning services include, but are not limited to, residential/commercial AC and heating, repair, service, installation, maintenance, and heat pump equipment repair.

Whenever you are looking for high-quality air conditioning and heating services at a day affordable price, we can help! We service and replace both commercial and residential HVAC systems in order to bring you the ultimate climate control. Autumn Mechanical proudly serves the Greater Houston area. Don’t hesitate, give us a call today to find out what we can do for your home or business.


Autumn Mechanical
18812 Tomato St.
Spring, TX 77379
(713) 864-8368
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