Air Conditioning: What's That Noise?


Central air conditioning units are generally very quiet. You may hear a low hum when they are running or a quiet pop when the compressor comes on, but that's generally the extent of it. Loud or odd noises, especially if they are new, typically indicate a problem with the system. Understanding the causes of various AC noises can help you troubleshoot a problem before it becomes too severe. This can mean the difference between a cost-effective repair versus a more expensive AC replacement.

Squeals and screams

Squealing noises that originate from the main unit generally indicate a problem with the belt or with the fan bearings. Fortunately, these are relatively common issues that only require a short service visit. The technician will simply replace the belt or repack the bearings, which will solve the problem. In some cases, it may be even simpler — the moving components may just need to be lubricated.

Loud, whistling screams are more alarming. These can indicate a refrigerant leak in the unit, especially if the AC stops cooling even when it is running. In this case, turn off the AC until you can have it serviced. You don't want to breathe refrigerant fumes.

Rattles and clicks

There are many causes of rattling and clicks. If the whole unit seems to shake when it's running, then it could have a failing blower. It could also be that the unit has shifted and that the anti-vibration pads it sits upon need to be reseated or replaced. You can also verify that it isn't simply from screws coming loose. Try to tighten the screws or clips that hold the housing in place to see if that fixes the problem before calling a tech.

Clicks and rattles may also come from the duct system. Some clicks are to be expected, especially if the unit has been off for a while. These are generally caused by temperature changes causing the metal to contract. In some cases, you may have ductwork that has come loose so it is rattling. A tech can inspect the ducts and retighten any loose parts.

Bangs and pops

Loud bangs and pops, particularly if they keep occurring or if other issues or noises accompany them, can indicate major problems. Sometimes it is as simple as a component inside the AC coming loose, but in other cases, it can indicate that a major part, such as the blower or compressor, is failing. To prevent further damage, turn off the unit until you can get a technician out to inspect it.

As you can see, there are many things that can lead to strange noises. Contact a residential AC service for help if you suspect a problem.


10 July 2019

Streamline Your HVAC System

As a DIY enthusiast, I started doing everything I could to make my household appliances more effective then ever before. I insulated my attic, worked on cleaning the vents around my kitchen appliances, and eventually turned my attention to my air conditioner and furnace. Unfortunately, the process of taking care of my HVAC system was more intense than I had originally anticipated. I realized that I needed to read about air conditioners and furnaces before I started tinkering around. I made this blog to showcase all kinds of different articles that talk about HVAC, so that you can become a more informed homeowner.