Your air conditioning system is supposed to keep your home or business comfortable, not create unsettling background noise. If you’ve recently noticed strange sounds coming from your AC unit, it could be more than just an annoyance — it might be a warning sign. At D-N-D Services, we’ve been helping Rockwall and surrounding areas stay cool and comfortable since 1997, and we’ve heard it all. Here’s a breakdown of what those noises might mean and why you shouldn’t ignore them.
1. Banging or Clanking
A loud banging noise usually signals a mechanical problem. This could be caused by a loose or broken part inside the compressor — such as a connecting rod, piston pin, or crankshaft. If the noise sounds more like clanking, it could mean that parts of the blower or motor assembly are out of balance and hitting other components.
What to do: Turn off the unit immediately to prevent further damage and call D-N-D Services. Our certified technicians can diagnose the problem and repair or replace faulty components before they cause a complete breakdown.
2. Buzzing
A buzzing AC unit may be caused by several things — loose parts, debris in the outdoor unit, a failing motor, refrigerant leaks, or electrical issues like a malfunctioning contactor relay switch.
What to do: Because buzzing could be a sign of an electrical hazard or refrigerant issue, it’s important to have a licensed HVAC technician from D-N-D Services inspect it. Don’t attempt to fix electrical issues yourself.
3. Squealing or Screeching
High-pitched squealing noises can often be traced back to belt issues or motor problems. In older AC systems, the blower motor might use a belt that becomes worn or misaligned over time. Squealing could also indicate that the bearings in your condenser fan motor are going bad.
What to do: While not necessarily an emergency, squealing means your AC needs attention soon. Routine maintenance from D-N-D Services can help spot and fix these problems before they lead to system failure.
4. Clicking
It’s normal to hear a click when your AC starts or stops. But if the clicking is constant or unusually loud, it might signal a defective thermostat, relay issue, or failing control board.
What to do: Electrical control issues can prevent your AC from functioning correctly or starting at all. Have our team take a look — our service techs attend routine factory training and are skilled in diagnosing complex control issues.
5. Hissing
A hissing noise might mean there’s a refrigerant leak — a serious issue that not only compromises cooling performance but could also damage the environment and your health. Alternatively, it could be air escaping from a duct leak.
What to do: D-N-D Services offers duct leakage assessments and refrigerant diagnostics. If your system is hissing, call us right away. We’ll perform a professional inspection and seal or repair the issue properly.
6. Rattling
A rattling sound often means something is loose — whether it’s debris caught in the outdoor unit or internal components starting to wear down. Over time, what begins as a small rattle can turn into a major repair if ignored.
What to do: Our experienced HVAC technicians can quickly identify what’s rattling and tighten or replace parts as needed.
Conclusion
Your AC system should run quietly in the background. Unusual sounds are your unit’s way of telling you that something’s not right. The earlier you address these issues, the more likely you are to avoid costly repairs or full system replacement.
At D-N-D Services, we’re more than just another HVAC company. We’re committed to exceeding your comfort needs — whether it’s residential or commercial. We’re proud to serve Rockwall, Rowlett, Mesquite, Garland, Greenville, Dallas, and surrounding communities with honest quotes, certified technicians, and unmatched service.
We’ve been on the Good Contractors List, hold an A+ BBB rating, and our technicians are NATE certified and factory-trained to work on all brands, including Carrier, Trane, Lennox, and more.
So if your AC is making odd noises — don’t panic. Call D-N-D Services today, and let our experienced team get your system running smooth and quiet again.
D-N-D Services Heating & Air Conditioning is the premier choice for HVAC services in Rockwall. With a team of highly trained and certified technicians, we have the expertise to handle all of your heating, ventilation, and air conditioning needs. Our commitment to customer satisfaction is unmatched, and we always go above and beyond to ensure that your experience with us is positive. We use only the highest quality parts and equipment to ensure that your HVAC system is running at peak performance. Plus, we offer competitive pricing and flexible scheduling to fit your needs. Choose D-N-D Services Heating & Air Conditioning for all of your HVAC needs in Rockwall.
