Here’s how to troubleshoot strange furnace sounds or noisy furnace ducts

All HVAC systems, to a degree, make noise while operating. However, how do you know if these noises are normal or an indicator that something is wrong? If you’re hearing strange furnace sounds or experiencing noisy furnace ducts, it could be either business as usual or a sign of trouble. In this article, we’ll review the wide variety of sounds that your furnace and air ducts can make, and which ones should lead to you giving us a call for furnace repair here in Buffalo and Western New York.

Start by ruling out potential furnace problems

Before you start thinking about what sounds are coming from your ducts, you’ll want to rule out that the sounds are coming from your furnace. There are several different furnace sounds that signal potential trouble. Here’s why you need to keep an ear out for popping, screeching, and rattling.

For help diagnosing noisy furnace ducts in your home, call the professionals at Reimer.

For help diagnosing noisy furnace ducts in your home, call the professionals at Reimer.

Popping Sounds

The sound of a loud “pop” coming from the furnace could be a sign that the furnace is igniting too much gas in the combustion chamber. In most cases, the root cause of this issue is a defective gas valve or dirty burners. Basically, what you’re hearing is a (small) explosion inside of the furnace.

This is something that you’ll want to get checked out by a gas furnace professional. Eventually, the furnace flame sensor—a safety mechanism that checks for the presence of a flame to ignite the gas—may kick in, shutting down your furnace.

Screeching Sounds

A loud screeching sound is not a natural part of a furnace’s cycle. It’s probably an issue with the blower fan’s belt. As these belts age and wear, they begin to fray and cause strange sounds. If you’re hearing a distinctive screech coming from your furnace, it’s probably not something you want to ignore for too long. Call our team and have us out to inspect the system.

Rattling Sounds

Chances are that you do not have a rattlesnake in your furnace, so the likely culprit of a rattle is something that is loose. The furnace produces a harmless low-frequency hum while in operation. Anything that’s loose—from screws and components to the heat exchanger itself—could start rattling from this natural vibration. Again, this is something you’ll want one of our technicians to help you diagnose. The rattling of a loose part is typically an early warning for an impending breakdown.

Diagnosing the sounds made by noisy furnace ducts

Now that you’ve eliminated the possibility that the noise could be generated by your furnace, it’s time to turn your attention to your ducts. Here are some of the most common sounds made by noisy furnace ducts while your heater is running.

Banging Sounds

Once you’ve ruled out the sound coming from the furnace itself, the next likely explanation of a loud popping or banging sound is the ducts. As hot air enters a cold duct, the metal expands and warps in response to the sudden temperature change. This leads to the metal “banging” as it shifts into place. This same phenomenon occurs when a duct, once filled with hot air, cools down after the furnace has been shut off. This sound is pretty harmless, and it’s natural to hear it whenever your furnace turns on or off.

Rattling Sounds

The rattling noise is most often caused by loose metal ducts that tend to knock against one another. This could be a sign that your ducts have leaks or gaps between them, which will ultimately have a negative impact on the performance and efficiency of your heating system. As ducts age, the connective sealing between them begins to deteriorate or loosen. This isn’t going to cause a breakdown or anything, but it’s still worth having a Reimer technician look into this winter.

Vibrating Sounds

A sound of vibrating or shacking of the duct walls normally occurs due to the blockage of the return side airflow. This usually happens due to a clogged filter that results in a drop in the air pressure that makes the duct walls vibrate and shake.

Booming Sounds

A loud booming noise coming from the ducts typically emanates from the plenum where all the ducts meet. This connecting point tends to endure the greatest swings in temperature. Inadequate expansion of joints or dampers contributes to the noise. What you’re hearing is a loud boom echoing through the supply ducts.

Whistling Sounds

In some cases, you can hear a whistling or rumbling noise emanating from the ductwork. The whistling noise is normally caused due to excessive airflow through the ducts. On the other hand, the rumbling noise could be due to pressure differences between the supply and the return ducts.

Call Reimer to have our team diagnose noisy furnace ducts

When it comes time to care for your furnace or your ducts, make sure that you hire an experienced and licensed furnace technician. An experienced technician will expertly identify and resolve all kinds of furnace problems due to which you can spend the entire winter months in total comfort and warmth.

At Reimer Home Services, our experienced techs are ready to assist you with diagnosing strange furnace noises and the source of noisy furnace ducts. Contact us today to schedule service here in Buffalo and Western New York.

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