Why Is My Furnace So Loud And How Do I Fix It?

Why Is My Furnace So Loud And How Do I Fix It

“Aren’t modern HVAC systems supposed to be quieter than ever?” You may be curious. “How come our furnace is so loud?” There are numerous causes of loud Furnace Noise. The issue is determining the root cause and how to remedy the situation. You might be able to solve some problems on your own. Others necessitate the Services of HVAC Specialists.

There are several reasons why a furnace makes a lot of noise while running. Assume you have a problem with a fan blowing hot air out of the ventilator. Worn fan bearings could cause this. These bearings should be replaced in this case.

If your furnace makes a loud noise right after it starts up, it could be due to a serious problem known as ignition delay. Unburned oil accumulates in the combustion chamber and ignites all at once, causing this phenomenon. This is potentially hazardous, and a qualified HVAC professional should be contacted immediately. Noise that necessitates countermeasures

Never disregard the sounds listed below. They alert your furnace to potentially dangerous problems (and possibly your home). Instead, for furnace assistance, contact a reputable heating and cooling company.

Also, Read: Furnace Maintenance Checklist – 7 Easy Steps

Whistling or High-Pitched Sound:

If your furnace whistles, it could be due to a duct gap. Check to see if you can hear where the whistle is coming from. It is frequently caused by a small hole near the connection point between the duct and the furnace, close to the blower.

If the whistle has recently begun to blow, the filter may be clogged, and the fan is sucking in as much air as possible. It will whistle when a significant amount of air is drawn through a small hole or gap. To test this possibility, remove the filter and see if it stops whistling.

If the filter becomes clogged with dirt and airflow is interrupted, you should consider replacing it (while worrying about buying a new one). This is beneficial not only for Reducing Noise but also for reducing fan motor wear.

Another reason for whistling could be that the channel is too small. Furnaces require more airflow and, as a result, larger ducts.


If your furnace or ducts are rattling, the problem is simple to fix. Here’s what you can do to silence the rattling.

  • Secure loose channels with screws
  • Tape loose ducts and other pieces of equipment.
  • Put a rubber or cork pad beneath the furnace. (You can probably lift the device with a pry bar and slip something thin underneath it.)

Booming or Banging:

There are two possibilities if your furnace makes a popping noise when you turn it on. The piping is “oil canned” or bends when the pressure changes. It could also be a small “explosion” known as an “ignition burst.”

Canning Line For Oil:

If the issue is an oily duct, you may be able to resolve it. You should carefully listen to the furnace to see if the knock is coming from the duct. If canned oil is the issue, your channel may have a weak spot that requires reinforcement. You might be able to repair it by screwing a slightly thicker piece of metal into the weak spot.

Ignition Deployment:

The other possible cause, ignition deployment, is less common but still concerning. A small explosion when the furnace starts, or a large burst of flames.

Check to see if a problem with the gas ignition causes the pop. Leave the furnace door open. You should be able to see what’s happening if you can see the furnace door. If not, pay close attention to the source of the noise. Check to see if the furnace door wobbles. If it does, try again with the burner compartment door open to see if the pop still happens and what happens.

Also, Read: How Often Should Furnace Cycle?

Loud Noise Causes:

  1. A Clogged Furnace Filter:

The most obvious cause of squeaks and whistles is that your furnace’s air filter is clogged with dust, hair, and dirt. Hmm.

Fortunately, this noise problem is easily and inexpensively remedied. Replace the existing filter with a new one if you’re using a disposable filter (or clean the filter for the permanent version).

If you don’t have a replacement disposable filter, we recommend removing it and running the furnace without one for a day or two until you get one from Ottawa Home Services. A clogged filter will continue to restrict airflow and may cause serious damage to your furnace’s fan motor and heat exchanger.

Replace or clean the air filter every three months and check it every 30 days. Always keep a supply of disposable filters on hand.

  1. Motor For The Blower:

The blower motor is another possible source of the squeak. This drives the blower, which circulates warm air through the ducts to heat the house. A blower motor requires proper lubrication to function properly (and quietly). The blower motor and the furnace can be damaged if there is insufficient oil.

Tip: Lubricate the furnace fan motor once a year by applying 2-3 drops of motor oil to the oil fitting.

  1. The Fan Wheel:

As it rotates, the impeller (the component powered by the blower motor that moves the heated air) can make an obnoxious metal-to-metal noise. This noise indicates that the impeller is misaligned and requires professional adjustment. TIP: To ensure peak performance, keep the blower wheel clean. An experienced HVAC company will perform annual furnace maintenance to ensure the blower wheel works properly.

  1. Heat Exchanger Cracked:

A dead heat exchanger could cause a rattling noise. Airflow is restricted when the furnace is not cleaned, and the filter is not changed. The furnace eventually reaches a point where heat can accumulate and damage the heat exchanger.

A ruptured heat exchanger is extremely dangerous because it can cause carbon monoxide to be released. It is a colorless and odorless gas that is extremely lethal. If you suspect this is the case, turn off the furnace and contact a qualified HVAC technician as soon as possible. Install a carbon monoxide detector to keep an eye on levels of this deadly gas. Schedule professional furnace maintenance regularly to ensure that your heating system is safe and operational.

  1. Filthy Burner:

Do you hear a popping or popping sound (almost like an explosion) a few seconds after turning on the furnace? This is a clear red flag. Fortunately, professional furnace cleaning solves the issue. Schedule regular annual Furnace Maintenance before such problems arise.

  1. Channel Problems:

HVAC ducts are made of thin sheet metal and provide excellent acoustic transmission. If the duct begins to rattle, it could be due to pressure differences between the supply and return ducts. You may also require reinforcement. The duct system is either out of the wall in one or two places, or the duct itself is faulty.

Also, Read: What’s The Best Furnace for A Mobile home?


These are just a few potential noise issues you might encounter when dealing with your furnace. While attempting to repair simple mechanical problems may save you money, if you have any serious concerns about the source of the noise, consult a qualified HVAC professional to be safe.


What kind of noise should a furnace make?

Furnaces are generally quiet, and most modern furnaces are designed to be so. A properly functioning furnace should not make a lot of noise, especially when it is first turned on. What is commonly repaired and the type of noise you are hearing will assist you in determining the problem with your system.

How can I make my furnace less noisy and more powerful?

  1. Find and replace any loose parts. Loose parts can make a lot of noise.
  2. Replace any damaged insulation.
  3. Connect the furnace motor.
  4. Make use of the return air duct
  5. Remove and replace the engine mounting gasket.
  6. Oil furnace motors and parts.
  7. Installation of the furnace on the support beams.
  8. Repair the noisy fan.

Why is the blower motor on my furnace so loud?

There are several reasons why a furnace makes a lot of noise while running. Assume you have a problem with a fan blowing hot air out of the ventilator. Worn fan bearings could cause this. These bearings should be replaced in this case.

Why is my furnace making such a racket?

For the furnace to function properly and efficiently, air and gas must be properly mixed. Excessive air and insufficient gas can result in the gas buildup and a loud booming sound.

Disclosure: We may get commissions for purchases made through links in this post.

About the author