Summer is a busy time and you probably don’t want to spend it dealing with air conditioner noise. But many of those strange noises can be signs of an impending breakdown. If you ignore the noise, you could end up with a much bigger problem. Here are some of the most common air conditioner noises, what they mean, and what can be done to get rid of them once and for all.

7 Air conditioner noises and their causes 

These air conditioner noises tell you that something is not working like it should. Some problems are more serious than others. Find out what’s behind the noise you’re hearing and what your technician can do to solve the problem.

1. Air conditioner is loud

Has your air conditioner always been too loud? If so, the AC noise may not be caused by something broken, but that doesn’t mean you have to live with it. Chances are it’s waking you up at night and disturbing your activities during the day. Here are some reasons why that can happen, and how to quiet things down:

Duct problems. If your ductwork is poorly designed and/or your ducts are not insulated properly, the airflow noise can be extremely loud and intrusive, especially at night. Rerouting ducts or adding duct insulation can help.

Poor equipment placement. If your indoor unit is located in an attic right above your bedroom, or your outdoor unit is outside your living room where you watch TV, that is going to cause annoying noise. It might be possible to move the equipment, or you can add sound carriers. If the equipment is older, consider replacing it with a VRF system that runs more quietly.

Oversized unit. Years ago, residential builders assumed that bigger units were better. Today we know that’s not true. But if your system is older, its capacity might be too large for your space, which can cause it to turn on and off frequently. Downsizing to a system with the right capacity can decrease the AC noise.

2. AC is running constantly

Does it seem like your AC is always running, even when it’s not that hot? Here are some reasons why:

Thermostat problem. If your controls are faulty, that can cause your AC to run constantly. Replacing the thermostat is a quick and easy fix.

Motor or fan problems. If there’s a problem with your system’s fan, or the motor that powers the fan, that prevents the coils from cooling. This is a simple part replacement.

Loss of cooling capacity. If your AC coil is dirty, frozen, or leaking refrigerant, or there’s some other issues with the cooling cycle, your system can’t cool effectively. So it runs constantly as it tries to reach the set temperature.

In all cases, you need a technician to diagnose the problem. If you see ice on your indoor unit, shut it off immediately and protect the surface underneath from water drips while you wait for repair.

3. Whistling

Does it sound like a hurricane blowing when your AC is on? These are the likely causes for your air conditioner making noises:

Clogged filter. If your AC’s air filter is clogged with dust, that can restrict airflow and cause that whistling sound. This is one reason you need yearly AC maintenance service. Changing the filter can quiet the noise, and keep your system working effectively.

Duct damage. If your ducts are damaged with holes or cracks, that can cause a whistling sound as the air leaks out. This can also cause a loss of cooling power and jump in your electric bill as the system tries to compensate for the lost air. Getting your ducts repaired will fix this problem.

4. Rattling

A loud rattle is an air conditioner noise you won’t be able to put up with for too long! Start by figuring out where the sound is coming from. Do you hear it near the outdoor unit, in the walls or ceiling? That can narrow down the possible causes:

Unstable unit. If your outside AC unit is no longer securely fastened to its base, that can cause a rattle when it runs. You’ll need a technician to replace the bolts and possibly rebuild the concrete base if it’s damaged. 

Fan problem. Loose fan blades can cause a rattling sound. This can be fixed by replacing the fan. 

Something loose in the ducts. You’d be amazed at the things we find rattling around in AC ducts, like toys, coins and loose screws. Your technician has equipment to get the item out and stop the rattle.

5. Squeaking

Does your AC sound like a car that needs new brakes? You might have one of these problems:

Parts need lubrication. Moving parts need to be oiled periodically, or they can get squeaky. 

Fan motor belt problem. A failing fan belt can also squeak, just like in a car. Replacing the belt is a quick fix.

Both of these issues can be prevented with yearly AC maintenance, since your technician will lubricate parts and proactively replace worn parts (such as fan belts).

6. Buzzing

If there’s a buzzing sound coming from your AC system, that’s a sign of an electrical issue. Turn it off while you call for repair. It may be a simple part replacement, but this is NOT a DIY situation. Get an expert who is trained to handle high voltage electricity.  

7.  Hissing

If you’re hearing a light hissing sound near your AC unit, that is a sign of a refrigerant leak. It may be a fairly large leak, so don’t delay. Turn off the unit and call for repair ASAP.

Bruni & Campisi can help with air conditioner noise in Westchester, Fairfield and Putnam counties

No matter what’s causing your air conditioner noise, you can count on Bruni & Campisi to get to the bottom of it. We’ll get to you quickly with 24/7 service, accurately diagnose the problem, and restore your comfort ASAP. Our experts can also offer helpful advice for repair or replacement decisions.

Schedule an appointment online, or call us now:

NY: 914-229-2809

CT: 203-263-9662

Bruni & Campisi provides 24/7 emergency service, installation, and maintenance for plumbing, heating, air conditioning, and generators in Westchester, Fairfield, and Putnam Counties. We also offer energy audits, sewer cleaning, and chimney cleaning. With our 40+ years of experience and training, you get the quality service you need.

Bruni & Campisi, Inc.

Serving Westchester, Greenwich and Stamford since 1979.

100 Grasslands Rd, Elmsford NY 10523

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