Tuckers Air Conditioning, Heating & Plumbing Blog

Breaking Down AC Warning Noises

Don't wanna hear

Air conditioning systems become quieter as technology advances. Today’s ACs can work almost unnoticed in a home—just the gentle blowing of air from the vents connected to the central cooling system, with most of the noise coming from the outdoor condenser cabinet, and even that is quieter than it used to be thanks to advances like scroll compressors. 

This general quiet makes it easier to notice an AC that’s making strange sounds. You don’t want these sounds interrupting your pleasant summer days, but they do have a useful side: they warn that you may need air conditioning service in Gaithersburg, MD to fix it! 

Today, we’re going to break down some of the more common warning noises your AC can make and what they may mean… 


This is actually a normal noise to hear from your air conditioner, at least at certain times. When your AC powers down after a cooling cycle, you can expect to hear clicking sounds from the machinery. This is standard for almost any machine as it powers down; cars do something similar. But when you hear clicking that is louder than normal or is happening regularly while the AC is running, it can indicate electrical troubles and bad connections. You’ll want experts to check this out ASAP.

Hissing & Bubbling

These noises come from a similar source: refrigerant leaks in the copper lines. Hissing is from the copper lines that carry the refrigerant when it’s in high-pressure gas form, and bubbling from the copper lines that carry the refrigerant in low-pressure liquid form. Losing refrigerant from an AC will eventually cause the entire system to break down, and the system will suffer numerous other troubles until that happens. We recommend you strike fast to have repairs done to seal the leaks and restore the proper amount of refrigerant.

Clanging & Banging

Sharp striking sounds aren’t something you ever want to hear from most mechanical devices. It usually means some moving part has come loose and is striking another part of the device. In an air conditioner, this often occurs with the indoor blower fan and the outdoor exhaust fan. The blades could be bent or the assembly misaligned. Shut off the AC switch to stop any further damage and call us for repairs.

Shrieking & Grinding

These mechanical noises are probably a warning of serious problems with the AC’s motors. Shrieking occurs when the bearings in a motor start to wear down, putting the motor in danger of burning out when they completely wear out. Fast action from pros can replace the bearings and rescue the motor. Grinding usually means a motor is already burning out and will need replacement.


An AC that’s making a humming buzzing sound probably has an electrical fault such as arcing. It can also come from failing motors, the contactor relay switch, or electrical connections. As with any electrical issue, you only want pros to take care of the necessary repairs.

At Tuckers Air Conditioning, Heating & Plumbing, we pledge to exceed expectations at every turn! Contact us today to arrange for AC repairs.