Loud HVAC Noise: What It Means And How To Fix It

It can be a nuisance to have a noisy HVAC system in your house, especially if you’re sensitive to sounds and need to operate it while enjoying your sleep.

Regardless of what season you’re in, having a noisy HVAC is a headache. However, if you pay close attention to these noises, you might be able to pick up on some cues that inform you on the condition of your system and what’s causing the noise.

While you might be able to identify the source of some HVAC noises, others might be hard to pin down or solve on your own. Examples of this include when your HVAC is making a loud humming noise. In this case, reaching out to a technician for help is the ideal thing to do.

So if you’re wondering why is your HVAC making loud noise, don’t worry. In this blog, we’ll cover the potential reasons and solutions of loud HVAC noise.

Causes of loud HVAC noise and their solutions

1. Noisy fan

If your HVAC equipment is making loud noises, the first thing to check on is the fan. Open your unit’s cabinet and check out any debris or dirt buildup. It could be the reason behind the irritating noises from your HVAC.

If you don’t end up finding any dirt or debris, proceed to check the fan blades. They could be loose or maybe rubbing against something as they rotate.

Thoroughly cleaning your fan is the first step to resolving this issue. A dirty fan is equal to noise and non-functional HVAC. Once you get rid of all the debris and dirt from your system, loud noises cease, and the fun will run smoothly.

As for the loose blades, fixing them is not a big issue. Use a screwdriver to tighten up the screws holding the blade. Also, check on the blades to see whether there are any damages. 

2. Blocked coil fins

Is your HVAC making a loud humming noise?  The culprit might be clogged coil fins. These blocked coil fins tend to be very noisy, and they affect the efficiency of your HVAC. With this issue, you can DIY or call for professional assistance.

The first step here is to vacuum the clogged coil fins with a brush attachment. It will loosen and get rid of all the debris and dirt. As you do so, thoroughly examine the fins. If they are bent, use your bare hands to straighten them. The entire process will help take care of any loud noises from your HVAC resulting from the fins. 

3. Moving parts friction

Your HVAC unit contains various moving components, such as the fan. When these moving parts rub against each other, they might produce some loud noises. In addition, they will experience wear and tear due the friction and heating.

Lubrication is the only way to solve this issue. Ensure that you lubricate all these moving parts to help reduce friction and heating. This will also prevent your HVAC from producing strange and loud noises, as well as speedy wear and tear.

It is important to take note of the type of lubricant you’ll be using to ensure your system is protected. Reach out to an HVAC unit manufacturer for assistance on what to use. 

4. Loose components

With time, most of the components in an HVAC might become loose. They mostly get out of balance due to vibrations, and loose parts usually produce loud, clacking sounds.

Therefore, whenever you hear such sounds from your system, you might be dealing with loose parts. To solve this, contact your technician, who should be able to tell you the parts that are producing these noises. Also, depending on the part or damage, they will recommend whether to replace or repair the problematic parts. 

5. Loose wiring

Loose wiring might also be another reason you have an HVAC making a loud humming noise.

If the wiring hasn’t been handled properly, this might be the source of the noise. In the worst-case scenario, loose wiring can cause an electrical fire, which can be quite dangerous.

While some homeowners might be able to sort the issue themselves, it’s not highly recommended. Instead, get in touch with a qualified technician who will examine and fix the loose wires.

6. Faulty thermostat

The thermostat produces a clicking sound during normal operations. The sound is usually heard when the device registers a different temperature range, above or below the set limit. This means that the sound is an indication that your system needs to take action.

However, in some instances, the clicking noises might be louder, and this might indicate several things. For instance, it might be a faulty thermostat, or a sign that it needs a battery change.

7. Compressor problems

If your compressor is not functioning as it should, it might produce loud and strange noises. And the age of your HVAC unit usually brings about compressor problems.

In case your compressor has problems, you should call a technician to determine whether it needs replacement or repair. This way, you can enjoy a comfortable indoor environment without having to tune out the constant background noise a faulty compressor can make.

8. Moving screws

Whenever your HVAC unit is operational, it usually vibrates a fair amount. However, these vibrations might loosen screws from their fittings over a period of time. So if your unit begins to produce loud rattling noises, you might be dealing with some loose screws.

This shouldn’t be too much of an issue, as you can fix it quite easily.All you need is to identify the unfastened screws and screw them back using a screwdriver.

However, before you start fixing this issue, risk prevention is paramount, so make sure to switch off your system before starting this procedure. Tighten all the loose screws to their original place, then switch your HVAC on and test whether it still produces the rattling noises.

If the noises are still persistent, get in touch with an expert to address this issue. 

9. The age of your HVAC

Normally, an HVAC doesn’t operate in total silence. It produces some sound during operation, although negligible. However, some units, especially older models, produce quite a bit more noise in comparison with newer models.

The older models were not designed with quietness in mind, and there isn’t really much you can do to solve that issue. So, if you have an older HVAC model that’s constantly interrupting your peace and quiet with loud noises, consider purchasing a newer one instead.

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