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Quality Heating & Cooling Blog

These Sounds Could Mean You Need AC Repair


Your air conditioning system is designed to run silently. The only sounds you should hear it make are the sound of it turning on and off and the gentle whoosh of air coming from the vents. You might also hear the expansion and contraction of your ductwork and a clicking sound after it completes a cooling cycle.

It’s when you hear sudden, loud, and unusual noises that you know something is amiss. Your air conditioner will make noises when it’s struggling to do its job efficiently. Let’s review some of these strange sounds and what they indicate could be wrong. That way, you’ll know whether you need to call us for air conditioning repairs. 

Banging, Clanging, and Rattling

The sound of metal striking metal is unmistakable. It usually means that a screw is literally loose somewhere in your air conditioner. A single screw or bolt that’s loose will make a rattling noise as it bangs against other metal parts. Luckily, a few loose screws are an easy fix for our team.

Unusually loud banging and knocking could be a sign that something is wrong with the blower fan. This is the component that blows the cool air through the vents and into the rooms of your home. Sometimes the fan blades become bent or misaligned and when this happens, it’ll bang against its metal housing. Whatever is causing these noises, it’s better to have them checked out sooner rather than later. 

Whistling or Hissing

Your AC can make a whistling or hissing sound for the same reasons a human can: by pushing air through a tiny opening. With an air conditioner, these sounds can be caused by refrigerant leaking through small holes or leaks somewhere in the system. 

Although your air conditioner has as much refrigerant as it should ever need for its entire lifespan, when refrigerant escapes through holes or leaks, your AC no longer has enough refrigerant to do its job. 

You’ll notice signs of refrigerant leaks via these noises. Because refrigerant is colorless and odorless, you won’t see or smell anything. When your AC no longer has enough refrigerant to work, it’ll work less effectively. You’ll notice your home isn’t cooling down sufficiently. Ice may develop on the evaporator coils. 

A refrigerant leak should be addressed immediately because breathing in refrigerant is a safety hazard. Our technicians will find the source of the leaks, fix them, and recharge the system if needed. 


As we mentioned, his noise is normal when it occurs at the beginning and end of a cooling cycle. Clicking at other times could be caused by faulty electrical components such as the thermostat’s wiring. However, in a worst-case scenario, the clicking noise could be caused by a “hard starting” compressor. 

The compressor is the “heart” of your AC system. This part controls all the other elements throughout your AC system. The aptly named compressor compresses the refrigerant in your system. When there are problems with the compressor, the entire system cannot function. If you’re hearing clicking noises, schedule an appointment with our team promptly. 

Contact Quality Heating & Cooling today for AC repairs in Middletown, NY. It’s not a Quality job, unless it has our Quality seal. 

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