When the weather turns hot and muggy, we turn to our HVAC systems to provide air conditioning for our homes and businesses. When these AC units are activated, they can make all sorts of noises, however there are many noises your air conditioning unit should NOT make, and if they are loud noises then there’s an even larger cause for concern.

Homeowners and business owners alike understand the importance of maintaining their cooling systems, including both typical air conditioning systems and heat pump systems, as well as indoor units and outdoor units and keeping the air filters and other maintenance items replaced. If those systems need troubleshooting it often can require the expertise of a trained HVAC technician, but this post will try to equip you with what to watch out for (or LISTEN FOR) to know WHEN to contact a professional AC repair service like Climate Control Heating Cooling & Plumbing.

1. Shrieking/Screeching

Do you hear a loud, mechanical noise coming from your air conditioner that you’ve never heard before? This is most likely a sign of a blower motor problem, or at least the sign of a fan motor bearing that’s worn-down (which is not inherently uncommon or bad, but should be repaired as soon as possible).

A worn-down bearing will eventually cause too much friction on the motor, and could permanently damage it, as well as cause issues in other vital systems, such as your compressor, condenser and condenser fan as well as impact airflow and performance. Our professional HVAC technicians will quickly and accurately replace these bearings in order to save your blower motor and prevent more damage down the road.

2. Grinding

Grinding or squealing noise is another indication of a possible fan motor problem. The most common cause of this sound is a motor that’s accumulated too much dust and debris, or has lost too much lubrication over time, causing a noisy air conditioner. Again, this is a normal part of AC wear and tear (and a likely cause we check for during maintenance). However, it should never be ignored.

Additionally, if the noise is accompanied by an acrid smell coming from the ductwork, it’s an almost definite sign that your motor is already overheating and that humming noise is going to go from an inconvenience to needing an AC repair company. Be sure to turn off your air conditioner right away, and give our professionals a call.

3. Rattling

This may seem like a minor problem, and in some cases it can be. Take, for instance, a loose cabinet door. You can resolve this by yourself, with nothing more than a few twists of a screwdriver.

It could also, however, be the sign of something more serious. You could have loose parts of AC components being knocked around in your blower fan, or bent fan blades, a wearing fan belt, deteriorated isolation feet, or more. It might even be that your AC system’s cabinet is coming loose from the foundation, or you could have damage to your ductwork. If you’re ever in doubt about what a certain sound means for your air conditioner, the best thing you can do is call in a pro.

4. Hissing/Bubbling

Both of these sounds, bubbling and hissing noise, indicate a detrimental problem for your air conditioner—a refrigerant leak. When your air conditioner makes cool air, refrigerant is a major part of that. Refrigerant is not meant to leave your air conditioning system, despite the common misconception that air conditioners consume refrigerant. Alas, it is not a fuel—it is regularly recycled throughout the air conditioner’s lifespan. Well, ideally it is, anyway.

If your system is losing refrigerant, it means there is a leak that must be accurately located and repaired. Without repairs, you could find yourself facing a completely broken down air conditioner in a matter of months or sooner.

5. Short Cycling

Short cycling is when the air conditioner turns itself on and off without completing a full cooling cycle. It can be caused by an electrical issue or a damaged compressor. There are two main problems that short cycling presents for the system. The first is that it prevents the air conditioner from cooling as well as it normally does. It can’t complete a full cooling cycle, after all. The second issue is that short cycling increases wear and tear on the system. The longer the air conditioner short cycles, the more prone to various other issues it’s going to become. If you let it go on long enough, it can shorten the lifespan of the air conditioner by a number of years. Make sure that you call for repairs as soon as you notice it making this noise.

6. Loud Buzzing Noises

Often these noises can be jarring if you’re close to the source, but if your air conditioner is making a loud buzzing noise, it can be very likely due to electrical issues. Parts such as damaged compressors, capacitors that had gone bad, or even loose wiring. When these parts cause electrical issues, it is also commonly accompanied by clicking noises as electrical relays are having issues making connections, causing electrical problems.

Strange noises and buzzing sounds are never fun to hear as a homeowner, but sometimes an air conditioner unit’s rattling noise can be from damaged isolation feet. That can also lead to clanking or banging noises as the system moves because the connection to the foundation is weakening.


You have access to a professional air conditioner repair company that has served the Greater Kansas City Metro for decades. When you need quality AC repairs in Kansas City, MO, contact Climate Control Heating Cooling & Plumbing, so you too can get Comfort & Care from the Team with the Bear!