August 27, 2019
Your air conditioner should be a background appliance — something you set and forget on a hot Georgia day. So when it starts rattling, banging, squealing, or making any other noise that grabs your attention, that's your system telling you something is wrong. At Henson Heating Air and Plumbing, we get calls all the time from homeowners across Gwinnett County who ignored a strange AC noise for a few weeks, only to end up with a much more serious — and expensive — repair. Don't let that be you. Here's what the most common AC sounds mean and when it's time to call a professional.
Why AC Noise Matters More Than You Think
Modern air conditioning systems are engineered to run quietly. When you start hearing sounds that weren't there before, it almost always means a component is stressed, worn, failing, or loose. The longer you let it go, the more wear it puts on the rest of the system. A small issue caught early might cost a couple hundred dollars to fix. That same issue left alone for a season can take out your compressor — and compressor replacements often run $1,500 to $2,500 or more, sometimes making full system replacement the smarter financial call.
Bottom line: if your AC is making a noise that sounds wrong, trust your instincts. Call Henson Heating Air and Plumbing and let us take a look before a small fix turns into a big one.
Common AC Noises and What They Mean
Banging or Clanking
A banging or clanking noise is one of the more urgent sounds you can hear from your AC. It usually means something has come loose inside the system — often a connecting rod, piston pin, or other component inside the compressor. It can also mean a piece of debris has gotten into the outdoor unit and is being tossed around by the fan blades. Either way, this is not a noise to ignore. If you hear banging, shut the system off and call us right away. Running a system with a loose or broken internal part can cause rapid, widespread damage.
Squealing or Screeching
A high-pitched squealing or screeching sound is most commonly caused by a worn or slipping fan belt, or by a motor bearing that needs lubrication. In older systems, belts were common — in newer systems, the most likely culprit is a bearing starting to fail in one of the fan motors. This is a repair that's usually affordable and straightforward when caught early. Left alone, a failing bearing can cause the motor to seize, turning a simple repair into a full motor replacement.
Rattling
Rattling sounds can come from a few different places. Loose panels or screws on the unit housing are a common and easy fix. But rattling can also signal loose components inside the system, debris in the outdoor unit, or early signs of compressor wear. A quick inspection by one of our technicians can identify the source and tell you exactly what you're dealing with. Don't assume rattling is always minor — let us confirm it before assuming it'll go away on its own.
Hissing or Bubbling
Hissing and bubbling sounds are often associated with refrigerant issues. A hissing noise can indicate refrigerant is leaking from a line or connection — you may also notice your home isn't cooling as well as it used to. Bubbling sounds often point to air or moisture in the refrigerant lines. Refrigerant leaks are not a DIY fix — handling refrigerant requires EPA certification and proper equipment. If you hear hissing near your indoor or outdoor unit, give us a call. Running an AC with low refrigerant causes compressor damage that can be severe.
Clicking
A single click when your AC starts up or shuts off is completely normal — that's just the electrical relay switching on and off. But if you're hearing repeated or rapid clicking, especially when the system is trying to start, that's typically a sign of a failing capacitor or a relay problem. Capacitors are what give your compressor and fan motors the jolt of power they need to start. When a capacitor starts to fail, you'll often see the system struggling to kick on, combined with that repeated clicking. This is a common and fairly affordable repair, but it needs to be addressed before the system completely fails to start.
Buzzing
Buzzing can come from a few different sources. Loose parts, a failing motor, dirty condenser coils, or electrical issues like a malfunctioning contactor can all produce a buzzing sound. Electrical buzzing in particular is something to take seriously — it can indicate arcing or a loose connection that poses a safety risk. If the buzzing is coming from the electrical components of your system, don't delay getting it looked at.
Humming
A low humming sound is often tied to electrical components — specifically a motor that's receiving power but not starting, or a loose electrical connection. You may also notice the system isn't cooling properly alongside the humming. Like clicking, persistent humming that wasn't there before is a signal that something has changed in the system and needs attention.
Loud or Excessive Running Noise
Sometimes the issue isn't a specific odd sound — it's that the system just seems louder than it used to be overall. This can mean the unit is working harder than it should be due to a dirty filter, restricted airflow, low refrigerant, or dirty coils. It can also mean the system is aging and components are wearing down. Either way, if your system sounds louder than normal without a clear external cause, a maintenance visit can identify exactly what's going on.
When to Call for AC Repair in Gwinnett County
The honest answer is: whenever something sounds different than it used to. Homeowners know their homes. If you notice a new sound — even a subtle one — it's worth a call. We serve homeowners throughout Loganville, Lawrenceville, Duluth, Conyers, Covington, Lithonia, Stone Mountain, Decatur, Oxford, and all of Gwinnett County. We offer 24/7 emergency service for situations where the noise is accompanied by a complete loss of cooling, a burning smell, or anything that makes you concerned about safety.
For situations that don't feel urgent but still need attention, we'll get you scheduled quickly. Our technicians will diagnose the sound, show you what they find, and give you a straight answer on what it costs to fix — no surprises, no pressure.
Prevent Noise Problems with Regular Maintenance
Many of the issues that cause strange AC noises — worn bearings, loose components, dirty coils, failing capacitors — are exactly the kinds of things our technicians catch during a routine maintenance visit. Staying on a regular maintenance schedule is the single best way to avoid unexpected breakdowns and keep your system running quietly and efficiently all season long. Ask us about our maintenance plan options when you call — plan members get priority scheduling and discounts on repairs.
Hear Something Strange? Call Henson Heating Air and Plumbing
Don't wait and hope the noise goes away. Strange AC sounds almost never resolve on their own — they get worse. Henson Heating Air and Plumbing has been serving Gwinnett County and surrounding communities for years, and our technicians know these systems inside and out. We install and service Daikin and Carrier systems, and we work on all makes and models. Financing is available for larger repairs or replacements.
Call us today or schedule online. If your AC is making a noise it shouldn't be — we want to hear about it before it becomes a bigger problem.
