What is the banging sound in my heater?

Author: Luz Barton  |  Last update: Tuesday, December 16, 2025

Air pressure buildup within your HVAC system can push against the walls of the ducts, causing them to expand, which causes a banging or popping sound several seconds after you turn the system on. Improperly installed ductwork often results in bending, which increases static pressure within the system.

Is it normal for a heater to make banging noise?

When heat hits the cold metal ducts, it causes expansion. When the heat cycle finishes, the ducts start to contract which may produce a loud bang. While these noises from your ductwork can sound concerning, there's usually nothing wrong with your ducts or ductwork system – it's just a normal sound.

How do I stop my heater from banging?

Check with maintenance, but you may be able to shut the valve before going to bed. That should shut off the heat to your bedroom and hopefully prevent the loud banging sounds. The other option for them would be to bleed the system, so that they can get rid of any excess air etc in the pipes.

What does a bad bearing sound like on a furnace?

Grinding and scraping furnace noises usually point to dry bearings within the furnace blower motor. These bearings need regular lubrication to maintain proper function. If you have a preventive maintenance plan with Estes Services, your technician handles this during an Atlanta furnace maintenance tune up.

Why is my heater making a tapping noise?

A worn-out igniter can periodically fail, and if it keeps trying to light the gas, your furnace will make a clicking sound. The noise may last until the flame ignites or the gas valve closes. This failure and its corresponding clicking noise can also result from the igniter's wiring coming undone.

What Makes Radiators Bang So Loudly?

Why is my furnace making a knocking sound?

If the blower wheel becomes unbalanced, you may hear knocking sounds when the furnace runs. Calling in a professional to clean and rebalance the blower wheel not only saves you from more costly repairs, but in a worst case scenario, an unbalanced blower wheel may explode.

What is the tapping sound in heating?

Whistling and tapping noises are common symptoms of internal mineral deposits as water struggles to flow through narrowed pipework. Similarly to air trapped in the system, you may also experience radiators that are hot at the top but cold at the bottom.

What are the first signs of bearing failure?

A sure sign that your bearing has failed is vibration. If the raceway surface of the bearing becomes damaged by abrasion, the rolling elements (the balls or rollers) will bounce around on the raceway surface during operation, causing high levels of vibration.

Why is my heater making a weird sound?

There are a variety of problems that can cause your furnace to produce loud noises. Types of noises such as scraping, banging, whistling, and popping may be a sign of a loose part, cracked heat exchanger, or dirty gas burners.

What does a worn pilot bearing sound like?

A worn or damaged pilot bearing will make a whining or grinding noise. It will be very loud if the bearing is completely damaged. It occurs whenever the crankshaft and input shaft are rotating at different speeds.

Why is my HVAC making a loud banging sound?

Loose or Unsecured Parts: Over time, components within your air conditioner can become loose due to regular wear and tear. When these parts move around, they can create banging noises as the unit turns off and on. Duct Expansion and Contraction: Your ductwork can expand and contract with temperature changes.

What is the banging sound in my heating ducts?

Banging Sounds Coming From the HVAC Ductwork

This type of noise usually occurs in quick, short bursts. It is the result of expansion and contraction in the duct walls as internal temperatures rise or fall. This type of noise can also be the result of pressure changes within the ducting.

Why does my radiator heater make a banging sound?

Why do radiators clank? Well, knocking, banging, and clanking radiator sounds are generally a sign of trapped water or air in the system. When either gets stuck, steam is prevented from moving through the pipe into the radiator.

How do I stop my furnace from banging?

Clean Any Dirty Burners

The bang that you hear is the sound of a larger volume of fuel finally igniting, creating a small explosion. This issue is called delayed ignition. If you suspect delayed ignition is producing the banging noise you hear, you'll need to clean your burners to stop the furnace from banging.

How do I stop my heater from knocking?

Bleeding your radiators will release any air that may be trapped inside. When air gets into your heating system, it can cause a banging noise because it increases the pressure in the system. Releasing pressure by bleeding the pipes of excess air can stop the banging noise from occurring.

What causes loud banging noise in a house?

The banging noise you heard is typically caused by your water pipes, and it is one of a few sounds that can come from your plumbing. While a water hammer could be the explanation, starting with a survey of all your visible water lines can help you fix or rule out any other causes.

Why does my heater make a knocking sound?

If so, then expansion and contraction are probably the culprits. Expansion and contraction occur when your metal ducts, pipes, vents, and other components make noises while they heat up or cool down. While hearing these parts clang and bang together can be alarming, it usually doesn't indicate you have an issue.

Is it normal for a heater to make popping noises?

Popping. If you hear popping sounds and you don't have a bag of popcorn in the microwave, you could be dealing with dirty furnace burners or damaged air ducts. When the burners are dirty, the buildup prevents them from igniting, which causes too much gas to build up, making a popping sound.

Do bearings give warning before they fail?

This is reality, and can happen if you fail to notice the signs the wheel bearings are deteriorating and need immediate repairs. Your wheel bearing might be bad if you hear unusual sounds like humming, squeaking, or clicking. Some experts say a bad wheel bearing can sound like a bird chirping.

What are the symptoms of a bad rod bearing?

Two of the most common symptoms that point to a faulty rod bearing are rod knock and illuminated warning lights.

Why is my heater making a ticking noise?

The common sources of a furnace clicking sound are:

If it's faulty or dirty, it won't send the signal and the ignitor will click. Ignitor flame — The flame itself can run too cold to burn the gas or oil effectively, so the ignition clicks for several minutes or unendingly.

What is the thudding sound in pipes?

What causes plumbing pipes to make a banging noise? If you hear a vibrating, banging or pounding noise when taps are turned on or off it's usually due to hydraulic shock in your plumbing pipework. Hydraulic shock is more commonly known as “water hammer”. The banging noise you hear is the result of vibrations in pipes.

What does knocking sound on the heat pipe mean?

2) Trapped Air in the Pipes

Trapped air in the pipes, also called airlocks, can be a major cause of noisy heating pipes. The airlocks or air bubbles in your pipes create a loud sound that can sound like banging, knocking, or clunking.

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