If you are hearing a boom sound coming from your furnace, the combustion chamber and burners can become clogged from grime and build up.
Replace Your Dirty Furnace Filter
Heat causes the metal material to expand and push outward – when the cycle stops and the metal cools, it contracts and pops back into place, generating that loud banging sound that you hear indoors. In this case, the best solution is simply to change the dirty air filter.
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.
While it's normal to hear your furnace whenever it turns on and runs, if it makes a boom, bang, or popping sound when it starts up, the equipment should be inspected by a professional HVAC technician.
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.
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.
Replacing a furnace blower motor costs $560, on average. Depending on the size and type of motor, most people pay $300 to $900. The average blower motor replacement cost is $560, but the final price depends on labor fees, as well as the cost of the parts.
You are most likely hearing a delayed ignition. When too much gas builds up in the combustion chamber and the ignition is delayed, your furnace experiences a small gas explosion. This can be caused by low gas pressure, clogged burners, and dirty equipment.
If you're hearing a loud banging or booming noise, this could indicate your furnace has dirty burners. This is hazardous as it can hinder the ignition. This delay in ignition triggers a gas build-up, producing a little explosion when it finally does light. Your burners should be regularly cleaned to avoid this issue.
This typically happens in furnaces that haven't received regular maintenance. A dirty burner might sound innocuous but it can be dangerous. The booming noise you're hearing is caused by a delay in ignition due to a buildup of dirt on the burners.
The Blower Motor Bearings or Wheel May Be Bad
A bad blower wheel can cause the loud, high-pitched sound you're hearing. The good news is it's an easy fix if this is the problem. You can replace it yourself or call a technician to come out and do it for you. A bad motor can also cause an annoying noise.
If you hear similar clanging or loud banging noise in the walls, it can be a sign of clogs or air pressure in the system called a water hammer. If you don't resolve the problem, it can cause damage to the pipes, so consult a professional.
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.
Since your heating system works in a closed loop, water travels from the boiler to the line of radiators and back. End-of-the-line radiators are being warmed by water that's already released a lot of its heat. The banging noise occurs when new hot water is released into a radiator that contains standing cold water.
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.
Thumping sounds that come from your furnace could indicate that a motor or blower wheel is out of balance. This could cause big problems for your mechanical equipment down the road. It's best to have an HVAC professional take a look and fix a small problem before it becomes a big one.
If your furnace is making an obnoxious noise, it's likely because the furnace blower motor is turning on and off as part of normal heating furnace cycles. Make sure your thermostat is set properly to the desired temperature and off when you don't need heat (like overnight).
Instead, you should take immediate action and contact an HVAC professional. A cracked heat exchanger can produce different sounds, including popping, banging, whistling, or scraping.
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.
Banging Sounds
If your furnace is making a loud booming or banging noise, the problem may be caused by a small gas explosion that happens when there's a delay in ignition. Gas can build up in your combustion chamber when the gas burners in your furnace do not ignite on time.
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.
If you suddenly hear loud and strange sounds like squealing or grinding, these are symptoms of a bad furnace motor blower that can signal signs of motor bearing problems or a damaged belt in older belt-driven models. Repairs may be possible or it may be time to replace the blower motor entirely.
Undo the screws on the motor to remove the belly band. The rotation of the motor needs to match the direction of the fans, so position them accordingly. Attach the new motor to the belly band. Center the new motor on the fan wheel, fasten the bolts, and connect the capacitor.
Furnace: A blower motor in a furnace can last a minimum of 10 years but up to 20 if you schedule regular maintenance to keep your unit in good condition. Heat Pump: Like a furnace, a blower motor in a heat pump can last at least 10 years, and up to 15 if the unit undergoes regular maintenance.