Why is My AC System Making a Loud Noise When Starting or Shutting Down?

By Ideal Conditions | February 14, 2020

Life is only comfortable as long as everything works, and everything works precisely as it should. Your AC system may be working as you expect it to, but you’ve started to notice that whenever you shut it down or start it up, it makes a loud noise. As AC units are not designed to make loud noises upon start-up or shut down, something clearly is wrong. The question, though, is what is wrong with your AC unit?

Top Reasons Why Your HVAC System is Making a Loud Noise

There are quite a few reasons why your AC system could be making a loud noise when starting up or shutting down, a few of which are listed below:

  • Ducts Expanding and Contracting – If you have ducts that are made of sheet metal, then the noises you are hearing are when the ducts expand and contract from pressure and temperature changes. Metal expands when it is hot, and contracts when it is cold.
  • Faulty Compressor – You may have a faulty compressor motor if you only hear a loud noise when you turn the unit on. If your AC unit is struggling to keep your home cool, then this is another symptom of a fault with your compressor motor.
  • Issues With Dampers in Your Home – Many AC units are fitted with ‘dampers’ so that they can control the cooling airflow that reach different parts of your home. If the noise is a ‘slamming’ noise, then it is likely that the dampers are closing once your AC unit is shut down.
  • Fan Problems – The fan or air handler that’s within your AC system can cause the blower wheel to collide with another part of the unit if it is not working properly. This usually happens when the fan’s mounts become loose over time. If the fan is speeding up or slowing down, then it is being thrown off balance.
  • Loose Parts: Over time, screws, bolts, and other components can become loose, causing rattling or buzzing noises.
  • Motor Problems: A failing motor can make a humming or buzzing noise.
  • Refrigerant Leaks: A hissing or bubbling noise could indicate a refrigerant leak.
  • Dirty or Clogged Filters: If the filters are dirty or clogged, the unit may make a whistling sound as it struggles to pull in air.
  • Blower Wheel Issues: If the blower wheel is out of balance or damaged, it can cause a loud noise.
  • Compressor Issues: A failing compressor can make a loud or high-pitched noise.
  • Damaged Insulation: If the insulation inside the unit is damaged, it can cause a buzzing or humming noise.
  • Obstructed Airflow: If something is obstructing the airflow, such as debris in the vents, it can cause a variety of noises.

The good news is that all these issues are completely solvable, as long as they are dealt with quickly and are not left to become worse. The rule of thumb is that when your AC unit starts banging, you start calling … the experts in to come and sort out the problem!

If you think your AC system needs a little bit of TLC, or if you feel your HVAC system is not performing as it should, or if it is still making really loud bang noises, then please get in contact with us here at Ideal Conditions. We have all the expertise that’s required to get your HVAC system back up and running as it should. You can contact us at (904) 379-8762, or you can use our online contact form.  We offer 24/7 Emergency HVAC repair Services. We are here when you need us – Day or Night. Call Today.

 

Posted in HVAC