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Why is my air conditioner so loud?

Jun 04, 2019

Two large grey air conditioning units outside a home in the D.C. region.

Image source: The Spruce

On a hot summer afternoon in Northern Virginia, air conditioning is something all homeowners are grateful for. However, a loud air conditioner can become more of a nuisance than a blessing over time. Plus, a noisy air conditioner could indicate that your system is operating inefficiently, leading to energy loss and higher utility bills.

Read more: 3 Ways to Save Money on Air Conditioning this Summer

If you’ve noticed that your air conditioner seems to run louder than normal or has suddenly started making unusual noises, there may be a more serious problem with your HVAC system at hand. Let’s explore the types of noises air conditioners make and the underlying causes of those noises:

Types of HVAC Noises

When operating efficiently, your air conditioner should be relatively silent, with the exception of a minor humming sound that happens when the system turns on or shuts down. Older air conditioning units may hum or vibrate a little louder than newer models, but some noise doesn’t necessarily indicate that your HVAC system is falling apart. 

Read more: Understand How Heating and Cooling Maintenance Works

However, an A/C that runs at a deafening volume or makes strange noises probably requires more immediate attention. Contact an HVAC professional if your air conditioner makes any of the following sounds:


One of the most common noises homeowners hear when the A/C is running is a popping sound, particularly when the system turns on and off. This sound is actually coming from your home's ductwork rather than the air conditioning itself, so there's no real cause for concern. Over time, your ducts warp and the joints loosen, which creates a strange popping sound as forced air flows throughout your vents. 


If your outdoor HVAC unit is producing a shrill, whistling noise, there could be too much pressure building up within the system, which could cause serious damage to the machinery and put you and your family in danger. Be sure to shut down your air conditioning right away and contact an HVAC repair company if your air conditioner starts making this noise.


A hissing noise coming from your air conditioner likely indicates a refrigerant leak, which should never be ignored. Not only can a refrigerant leak lead to ineffective cooling, but it can be dangerous, especially if touched or ingested by young children or pets that may play near the outdoor HVAC unit.


Electrical issues are often to blame for buzzing sounds coming from your HVAC system. Do not attempt to remedy any electrical issues yourself – it is extremely dangerous! Be sure to contact an HVAC professional or licensed electrician to assess the electrical damage as soon as possible.


A rattling noise coming from the outdoor HVAC unit could be caused by some sort of obstruction, like leaves, twigs, or other debris, that’s fallen into the unit itself or has made its way into the ductwork. Pay attention to the type of rattling sounds you hear – a light clang every now and then is likely nothing to worry about. However, loud, metal-on-metal clashing could be due to loose bolts or screws. If that’s the case, you’ll want to get to the root of the issue and make any necessary repairs.

Solutions for a Loud Air Conditioner

A loud air conditioner isn’t always just a nuisance — it can be a sign of greater HVAC problems that need to be addressed. Check out these tips to help reduce the noise produced by your HVAC system:

Relocate HVAC Unit

If your HVAC system is running properly and you’re still suffering from a loud air conditioner, it could be related to the location of your HVAC system. Your HVAC layout will have a significant impact on the level of noise you hear in certain rooms of your home based on proximity to the exterior unit. If possible, it may be worthwhile to consult a contractor about relocating your HVAC unit to minimize the noise impact.

Alternatively, if you live in an apartment building or another type of home with a larger interior unit, consider better insulating the HVAC unit to create a sound barrier that can help increase home comfort.

Replace Blower Motor

Many HVAC systems function using an A/C blower motor, which can become noisy as it ages. Newer HVAC models are being built with much quieter brushless, D/C variable speed motors. If a loud air conditioner is giving you grief, ask your air conditioning repair company about replacing your blower motor. A qualified HVAC technician will help you determine whether or not that solution is right for your home’s system.

Change A/C Filters

One of the most important — and often ignored — HVAC maintenance tasks is replacing air filters. Dust and debris clog filters over time, which makes your HVAC unit work harder to keep your home cool, potentially causing damage to the system. Be sure to keep an eye on your A/C filters and replace them by the recommended date.

Schedule Routine Maintenance

Prevent noise-producing damage to your HVAC system by scheduling routine maintenance at the start of each cooling season. During your annual tune-up, your HVAC technician will be able to identify and repair any issues before they become major problems.

Read more: 5 Questions for Your A/C Repair Company

Enjoy a quiet summer with help from CroppMetcalfe.

Don’t suffer through your summer with a loud air conditioner. If you’ve noticed that something doesn’t sound quite right when your A/C is running, contact one of CroppMetcalfe’s 5-Star Technicians. We’ll work with you to diagnose and repair the problem quickly and painlessly. Call 703-698-8855 or submit an HVAC service request online today.


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