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Serving Maryland and Washington, D.C.

Serving Fairfax and Loudoun Counties and the
surrounding area

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Serving Maryland, Virginia,
and Washington, D.C.

Serving Maryland and Washington, D.C.

Serving Fairfax and Loudoun
Counties and the surrounding area

24 Hour Emergency Services, 7 Days a Week

Home of Mr. Heat Pump

B&B Air Conditioning & Heating Service Blog

5 Noises That Mean You Need AC Repair

Unusual sounds coming from your air conditioner are always an early heads-up that something is going wrong. You should pay close attention to these warning signs and schedule an air conditioning service appointment sooner rather than later.

Scheduling AC repair in Alexandria, VA, after you hear the usual sounds is the best way to take care of your system. You can keep reading to learn more about sounds that can indicate something is going wrong inside your air conditioner that needs to be addressed.


If you hear whistling, it can be caused by a couple of different problems. The first is a refrigerant leak. The refrigerant inside of your air conditioner alternates between being a liquid and a gas. If there’s a hole in the line where the refrigerant is in its gas form, it will make a whistling sound. Refrigerant leaks are dangerous because refrigerant is a chemical that can pose harm to your family and home.

But it’s also possible that you have small, pinprick holes in your ductwork. When air blows through your ductwork and escapes through these tiny holes, it may make a whistling sound because of the pressure. No matter what the reason for whistling is, it’s always a good idea to get it checked out so that our team can fix the problem before it gets worse.


Sometimes loose fan belts can cause a screeching sound as they wear out. But screeching can also come from your compressor motor if the bearings are going bad. This high-pitched sound can be very alarming, and any time you hear it you need to turn off your air conditioner right away to prevent damage from spreading. Then schedule an appointment with our team so we can fix it and get your air conditioner running at its best again.


If you hear a knocking sound, that usually means that a component is not secure. Something may be loose and moving freely through your air conditioner, bumping up against other parts as it goes. But it’s also possible that a component is only beginning to come loose and knocking against a side during operation. Either way, you want this part to be secured again. Even if your air conditioner is still operating, great, a loose part moving around could cause a lot of damage if left unaddressed.


You may hear your air conditioner click as it turns on or off before and after a cooling cycle. However, you should not hear clicking at any other time. Hearing clicking too often may mean that your air conditioner is short cycling.

Clicking that is persistent and doesn’t stop may mean that your air conditioner is struggling to turn on for a cooling cycle. Since the compressor is a very expensive part to replace, you definitely want to get clicking checked out, even though it can be a very quiet noise that doesn’t seem like a big deal.


Rattling is another sound that can be completely normal in some contexts. When temperatures are changing, you may hear your ductwork rattle gently as it expands or contracts. However, this rattling should not last long or happen very often.

If you do hear persistent rattling, there’s a good chance that some of your ductwork is loose. It may be preventing cool air from reaching the walls of your home. It may also impact your indoor air quality by allowing dust and dirt to get inside.

B&B Air Conditioning & Heating Service. We are always there when you need us. Schedule an appointment today for air conditioning service.

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