Common Furnace Repair Noises: What They Possibly Mean | Fort Worth, TX

Common Furnace Repair Noises: What They Possibly Mean | Fort Worth, TX

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In a perfect world, your HVAC system should function efficiently all year round. But that’s not always the case since from time to time; it may experience some mishaps. When you start hearing banging, screeching, rapping, scraping, and some funny noises, especially from the furnace, you must respond quickly and determine the source of the noise. Some noises produced by the furnace may be harmless, but there are some sounds that you should not ignore unless you want to find yourself in a chilly house during the frigid winters in Fort Worth, TX.

In this blog post, we’ll help you know about some of the strange sounds produced by your heating system and what they mean for the condition of your equipment. Keep reading to know which sounds mean danger to avoid the need for an expensive furnace repair service or even replacement.

But first things fast, it is essential to know that some noises from the furnace are okay and should never cause concern, including:

Chirping noise: This is a natural noise from the furnace mechanisms.

Rattling sounds: They should not cause panic because they occur when the furnace is cooling after a cycle.

Crackling sounds: The metal parts cool down at the end of the heating cycle, hence these noises.

Pinging sounds: You may have heard them due to metal contracting in the duct system.

A faint hum and a slight click: This is a familiar sound produced when the burners ignite.

Beware of These Furnace Noises

Furnace Banging

You don’t have to be a furnace repair expert to know that a loud booming or thudding sound from the furnace is a sure indication of a malfunction. Surprisingly, some folks in Fort Worth, TX, will ignore such sounds if they are not persistent until it becomes a huge problem.

Then what does this loud bang mean? When the furnace kicks on and produces a loud sound, the ignition could be having a problem. In everyday situations, the gas valves open when the furnace gets a signal from the thermostat to start a cycle, and the ignition system ignites the gas immediately.

However, when the ignition system has a problem, little gas will accumulate in the combustion chamber, thus a banging noise is produced when ignition occurs because of the gas built up in the chamber. To avoid such issues, it’s important to understand things that could affect gas ignition in a furnace.

The first factor could be dirty or clogged burners or low gas pressure, preventing ignition until a remarkable amount builds up in the chamber. Also, there is a pilot light; the gas may fail to ignite quickly because of a weak flame. Lastly, it’s common to find furnaces with electronic ignition with a malfunctioning ignition system.

When you experience the above furnace problems, it would be best to have a qualified technician conduct a furnace repair as soon as possible.

Banging noises from the furnace can be due to the expansion and contraction of the ductwork. This happens because the warm air that makes your home cozy arrives via ducts made from thin metal. When heated, this metal will expand and when the furnace cycles off, it cools down, hence contracting.

Due to the expansion of the metal ducts, a banging noise is produced, which should not worry you. But if you find the noise annoying, there are things you can do to prevent the noise. You can have a furnace repair professional in Fort Worth, TX, replace the rectangular ducts with round ones or remove the thin metal and install a thicker one.


When your furnace produces a sound like a tea kettle, then something is wrong with the system. This whistling occurs when something interferes with the airflow. In most cases, it could be a blockage, especially an air filter that needs to be cleaned or replaced. Other causes include a blocked return or objects in the ductwork and closed vents. Sometimes malfunctioning burners or blowers in the system can cause the whistling, hence you may need a repair service.

Furnace repair services may not be necessary because you can fix the whistling sound by cleaning filters and ducts or opening up the dampers and vents.

If the problem does not go away, you can hire a furnace repair technician to fix or replace the furnace. For instance, when the whistling noise happens because the furnace is vast for the ductwork or too big for your house then a replacement is unavoidable.


When your furnace experiences some malfunctions, you’ll start hearing some knocking or clunking sounds. This could be an issue with the fan, especially if the blower fan becomes disarranged and the blades hit the walls or other furnace parts.

Also, when the fan belt splits or cracks, it can cause clunking noise as it bumps into other materials while rotating. When the knocking sound occurs continuously while the furnace is operating, it’s better to switch it off and call a furnace repair technician to check it.


Loud rumbling noises from a furnace should raise the alarm for Fort Worth, TX, homeowners. A normal functioning furnace will produce a roaring sound or a gentle woosh when it powers on to complete a cycle. However, if you hear a low rumble instead of the gentle roar, it could be a sign of trouble, and a furnace repair will be the best option.

If it’s a faulty burner, you’ll notice that the loud rumbling continues even after the furnace is off. This is because of the gas or oil in the combustion chamber after the furnace completes the cycle. This fuel continues to burn, hence the rumbling noises from the furnace.

The moment you notice this problem, immediately switch off the furnace and call a furnace repair service provider because the extra fuel in the combustion chamber causes high levels of carbon monoxide, which could be lethal to you and your family.


This sound is familiar in many furnaces. When the burner ignites, the furnace generates a humming noise, followed by a clicking sound in some cases. If you just purchased a new furnace, the transformer can hum as it adjusts the current flowing to the appliance.

But the humming sound should raise eyebrows when the furnace inducer motor produces a noisy hum throughout the operation, not just when the cycle begins. This could indicate an issue with the motor. Also, when the fan starts to wear out, it produces a loud hum. Always note the volume of the noise and the time it occurs. You should seek a furnace repair service when it happens throughout the cycle.

Loose ductwork causes the humming sound when air passes through the HVAC system, causing the ducts to vibrate. A furnace specialist will resolve the issue by fastening the joints between ducts using extra sheet metal screws and duct tape or additional straps to join the ductwork to the joints.

Another cause could be the electrical transformer. When an electrical current passes through the furnace’s transformer, a loud humming noise will be produced, which is not dangerous. You can reduce this humming sound by tightening the bolts that secure it or have a furnace repair service provider in Fort Worth, TX, check it out.

Lastly, loose parts can cause a humming sound. Due to intense activities in the furnace, some components loosen up from vibrations, hence the loud humming noise. Before seeking furnace repair services, you can check if all bolts are tight.

Screeching or Scraping

If you ever hear this noise, which sounds as if a piece of metal is being pulled over another metal, then have a furnace repair expert in Fort Worth, TX, check it out promptly. The common culprit in such cases is usually a loose blower fan that’s being dragged across the furnace casing. This issue only worsens with time, and if not fixed, metal filings will be produced due to the wearing process and fall into other parts.

Since fillings are small, they will move into the smallest openings causing massive damage to the electrical wiring, boards, and other moving parts. If they are steel shavings, they may hinder the effectiveness of the electric motor, causing failure. Always respond to such issues promptly to avoid costly furnace repair expenses and inconveniences.

Heat Pump Loud Vibration

This problem is more common for homeowners utilizing a dual fuel system. For starters, a dual-fuel heat pump works together with a furnace. In the summer season, the heat pump acts as a high-efficiency central air conditioner. At the same time, during fall and spring weather, the pump helps homeowners benefit from economical and efficient heat. During the chilly winters, the pump will switch off, and the furnace takes over.

When your heat pump is in its top-level condition, it’s usually quiet. When you start hearing an odd noisy vibration noise from the heat pump, a problem unfolds, and you need to take a few measures to rectify it.

Often, these loud vibration noises are due to an uneven surface. It’s recommended that you put a rubber pad beneath the heat pump to decrease the noise and create a more level surface. Sometimes the humming noise could happen due to loose screws or other parts in the heat pump. If the noise seems persistent, it is advisable to contact a furnace repair technician in Fort Worth, TX.

Rattling Ducts

Unlike other sounds, rattling air ducts should not be a cause for alarm; they could mean a minor issue with your heating system. Rattling noises coming from the air duct and, in most cases, mean that there is something loose with the duct-like joints and that heat could be escaping from those spaces.

When the duct is smaller than the vent opening, it can cause a rattling sound when air passes over the loose ducts, which clatter or bang against each other. Although the problem may not be that critical, it indicates that you are losing heat, translating into higher energy costs, hence you may need to seek furnace repair services.

Furnace Buzzing Noise

The furnace’s loud buzzing noise could be due to an off-kilter blower or excessive dust or obstructions in the fan and blower motor that can be cleaned. When the blower motor is failing, it can produce a buzzing sound, hence it would be best to have a furnace repair technician inspect it.

When you notice the buzzing sound when the furnace is running, it could be loose access panels or components. These loose components will vibrate excessively, creating this irritating buzzing sound when the furnace is running.

A furnace repair technician could resolve this problem by tightening all screws and securing the furnace exterior’s access doors. A buzzing-type sound generated from the transformer box that’s located near the furnace is typical. Still, you can inspect to see if it is securely mounted to prevent the buzzing noise and avoid future damage to the transformer box.

Fix Furnace Noises with One Hour Air Conditioning & Heating of Fort Worth

Now you know the normal sounds and the ones that could indicate a significant heating system malfunction or that your furnace is beyond repair. At One Hour Air Conditioning & Heating of Fort Worth, we have trained furnace repair experts who will conduct a thorough inspection of your furnace to get a clear picture of the problem and offer long-lasting solutions.

We understand how expensive repairs can be, but at times the best solution will be a furnace replacement, especially if the system is beyond its estimated service life or experience repeated problems. Our technicians will be happy to offer you a free quote for new furnace installation and help you select an energy-efficient, high-performing heating system for all-year comfort. Don’t wait! Call us today, and our experts will help you remove strange sounds from your furnace today.