Why does my furnace make a popping sound?

Author: Filiberto Volkman  |  Last update: Tuesday, September 30, 2025

Banging and popping sounds in a furnace are usually related to the natural expansion and contraction of the metal ductwork. As the furnace heats up, the ducts expand, and as it cools down, they contract.

How do you fix a popping furnace?

Clean the Furnace: A buildup of dirt and debris inside the furnace can also contribute to popping noises. Cleaning the furnace, including the burners, can help resolve the issue. Replace Worn Components: If the popping persists, there may be a more serious issue, such as worn or damaged components.

Why does my furnace keep making a popping sound?

The blower in newer furnaces is much stronger than older models, leading to the contracting and expanding of the ductwork attached to it. As the motor kicks on, you'll hear this popping as the metal ductwork expands to accommodate the strength of the blower.

When should I worry about my furnace noise?

Loud Bangs, Rumbles, Knocks, or Booms

Loud noises like this are a sign of a build of gas in a furnace. The noise you hear can mean your heat exchanger is at risk of cracking. Even worse, it's a sign that something dangerous could happen if you continue to use your heater.

Why is my HVAC unit making a popping sound?

When ducts are too small, it can create a buildup of pressure in the system, which results in a clicking or popping sound. These noises can occur when the heating or cooling unit turns on or off, and sometimes persist throughout the cycle of the HVAC system.

There is a popping Sound When My Furnace Comes On Or Is Running?

How do I stop my heating ducts from popping?

Insulate Your Ducts

Insulating your ductwork will help dampen sounds echoing throughout your home. The insulation will also help retain heat, reducing the fluctuation between hot and cold ductwork. A more constant temperature will lead to fewer pops due to oil canning.

Why is my thermostat popping?

The underlying cause of a clicking thermostat is purely mechanical. A thermostat has a circuit inside it that is connected whenever your thermostat realizes it needs to change the temperature. As the two small relays inside connect and disconnect, you can hear a tiny “thunk” from them moving.

What does a failing furnace sound like?

Thumps and bumping noises, like an unbalanced washing machine, often indicate an unbalanced blower wheel or motor. This is a serious issue that requires immediate HVAC repair. The blower wheel and motor are major furnace parts and you don't want them bouncing around.

How much is a new blower motor for a furnace?

While costs can vary, homeowners can typically expect the following range: Standard Blower Motors: These might cost between $400-700, excluding labor. Advanced Multi-Speed or Variable-Speed Motors: These are generally more expensive, with costs ranging between $650-1250, not including labor.

Why does my central heating make a popping sound?

A bubbling or popping sound could either be a sign of low water pressure or, more seriously, kettling. The water pressure on your boiler should be set between one and two on the gauge. Anything below that is low pressure and could mean that the boiler struggles to fire up.

Why does my furnace sound like it's backfiring?

Delayed ignition is when that gas isn't ignited immediately, allowing the gas to build up in the furnace. The gas keeps building until—BOOM—it reaches a flame and finally ignites, causing a small explosion in your furnace.

What does it sound like when a furnace is going out?

We're here for the long run. So if you hear a squeal, a new click, grinding, or popping when your furnace is at any point in the heating cycle, it's best to have a tech take a look and catch things early.

Is it normal for a furnace to pop?

Banging or Popping Sounds

Banging and popping sounds in a furnace are usually related to the natural expansion and contraction of the metal ductwork. As the furnace heats up, the ducts expand, and as it cools down, they contract.

What causes a furnace fuse to pop?

In an electric furnace, if the thermostat wire touches the metal frame of the furnace, it can cause a blown fuse. When the wire touches the metal frame, it can deliver a higher voltage than the wires are meant to handle. This will cause a fuse to blow.

Why is my furnace so loud all of a sudden?

If your furnace suddenly produces loud, sudden banging or booms, you should call an experienced technician as soon as possible. These sounds could indicate stuck ignition, a potentially dangerous situation involving carbon monoxide which is deadly.

What is the average lifespan of a furnace?

What is the average life of a residential furnace? A furnace that receives regular maintenance can last at least 15 to 20 years, but completing annual maintenance and being diligent with repairs can extend the life of a furnace even longer.

Does homeowners insurance cover furnaces?

Your base homeowners policy will cover many types of damage to your furnace. An extra endorsement known as Equipment Breakdown Coverage (EBC) will give you additional coverage for certain types of mechanical or electrical failure.

How much did it cost to replace a furnace?

Electric furnace installation tends to be the least expensive, ranging between $3,000 and $7,000, according to HomeAdvisor. Installing a natural gas furnace falls in the range of $3,800 to $10,000, and an oil furnace ranges $6,750 to $10,0000.

Why do my ducts make a popping sound?

Ductwork responds to pressure changes at times by making popping noises. This is normal, so you shouldn't be alarmed if you hear it at times. That said, when air duct leakage lowers the pressure or a blocked vent raises the pressure, you may end up with more serious problems that need addressing urgently.

What is the most common furnace failure?

One of the most common furnace problems is a malfunctioning thermostat. A sure sign your thermostat isn't working properly is if your fan is constantly running. This will cause your thermostat battery to run, and cause your furnace to work inefficiently.

Why does my gas heater make a popping sound?

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.

What does a bad thermostat sound like?

If your thermostat is not working properly, you might hear rumbling sounds coming from the engine because the coolant in the radiator is boiling. It could sound like knocking, boiling, or gurgling.

Why is my heater making a clicking sound?

If your furnace is making a clicking noise, this is a sign of an issue occurring during the heating cycle. When you hear clicking from your furnace, you should contact an HVAC professional immediately, as this strange sound may indicate a faulty igniter or gas valve. Issues with these parts can result in a gas leak.

Can a bad thermostat pop a fuse?

Thermostat Shorts

These thermostats are prone to voltage issues that could cause your furnace fuse to keep blowing if the internal wiring touches the metal. If your wires cannot handle the higher voltage, your control board may blow out, preventing the draft inducer from starting.

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