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Furnace Making Static Noise? 4 Common Causes (+ Fixes)

As winter months draw closer, you start up the furnace to warm up your home. While a furnace is a valuable appliance, it can also be a nuisance if it’s making weird sounds in the middle of the night. A furnace making static noise is often related to faulty components.

Your furnace is making a static noise because the blower motor isn’t balanced, the blower is blocked or dirty, or there are problems with the burner. Potential fixes include fixing the blower motor, cleaning the blower, ensuring there aren’t any obstructions, and cleaning the burners.

With the information in this article, you’ll learn to pinpoint why your furnace is making a static noise. I’ll also explain how to fix each issue to help you restore the furnace’s normal operation while preventing the noise from reoccurring.

The Blower Motor Isn’t Properly Balanced

While there are a few possible reasons behind your furnace making static noise, the problem often lies with the blower. The blower works hard to ensure heated air is sent to all rooms in your house. The two primary parts of the blower are the motor and fan. 

This assembly is mounted in a specific position within the furnace. Its placement ensures air can be drawn from the burner and then pushed into the ducts that form part of the HVAC solution. When the blower motor or fan isn’t properly balanced, you’ll hear noises from the compartment that houses the assembly. 

How To Fix

An inspection of the blower motor should help you determine whether there’s a problem with the balance and positioning of its parts. This involves opening up the furnace and locating the blower. Here’s what you have to do:

  1. Remove the panel on the front of the furnace.
  2. Take a look at the blower motor and make sure it’s in the correct position. See if it leans toward one side. 
  3. If it does, check for loose screws. Fasten any loose bolts or screws, and the motor should pull back into position. 
  4. While inspecting the motor, check the fan as well. See if it’s leaning toward one side instead of having a straight alignment. If there’s an imbalance in the fan, inspect the rod attached to it. 

Here’s a video that shows you how to find the blower motor in your furnace:

There Are Obstructions in the Blower Compartment

If the blower motor and fan are aligned properly, you should look for any obstructions in the area. 

For example, this could be a wire that pushes against the fan. Since the fan rotates faster, you may hear a static noise as the blades continuously touch the wire. 

In this scenario, you need to be very careful and take action quickly. A wire that touches the fan blades could lead to serious problems. If the fan blades cut the wire in half, you’ll be facing some expensive (and potentially dangerous) electrical problems with the furnace. It’s even worse if it’s a power cable. When a power cable is cut, certain parts of the furnace will no longer be supplied with the power required to operate. 

How To Fix

Finding obstructions in the blower assembly should be easy. If you completed the previous step, you already know how to find the furnace’s blower assembly. Open it up again and take a look inside. See if anything is in the way. 

You should look for different types of possible obstructions, not just wires. This includes loose parts that hang near the blower fan. 

If you find any loose parts, try to figure out where they should go and fasten them. Loose parts aren’t only the cause behind the static noise, but they could also lead to problems in the future if you leave them broken. 

The Blower Is Dirty

Dirt can accumulate in various areas of the furnace. Most people clean out or replace the filter at frequent intervals, but this isn’t the only area that needs a thorough clean. The blower assembly can also become dirty. When this happens, it’ll affect the functioning of the blower motor and fan. 

In some cases, the accumulation of dirt, gas residue, and debris on the blower assembly causes a static noise in the furnace. The debris can even become thick enough to reduce air circulation — it blocks the air that flows through the blower fan into the ductwork. This can lead to frigid temperatures throughout your home. 

How To Fix

Thoroughly cleaning the furnace and blower assembly is an easy fix for this. Again, you’ll have to open up the furnace’s front panel. Here’s what you need to do:

  1. Power off the furnace.
  2. Unscrew the furnace blower and remove it. This will allow you to get into the harder-to-reach areas of the blower. 
  3. Clean the fan and motor thoroughly. Be very gentle to avoid damage to these parts. Use a toothbrush to loosen up any dirt and debris. Then grab a vacuum cleaner or canned air to get the loose dirt off.

The video below will guide you through the cleaning process of the blower fan:

There Are Problems With the Burner

The blower assembly is often the reason behind a furnace making static noise, but there are other possible reasons for the sound too. The burner is another part to look at when you hear a static sound from the furnace. 

The burner accumulates dust and other tiny particles over time. Since flames are generated on the burner, the heat can cause these particles to burn continuously. As these particles burn, they might create the buzzing/static noise you’re hearing.

How To Fix

Cleaning the burner should help in most cases. Here’s what you need to do:

  1. Open up the front panel and locate the burner. It’s close to the ignitor inside the furnace.
  2. Use a toothbrush to clean the burner. Make sure to reach into the small creases that you see in the burner. 
  3. After brushing, use canned air. The canned air will allow you to get rid of all dirt stuck in the nooks and crannies.
  4. Use a vacuum cleaner. This is an extra step that can eliminate any particles that the canned air couldn’t blow out.

Not sure if you’re doing it, right? Watch this video to learn how to clean furnace burners from start to finish:

Summary

A static noise coming from the furnace is irritating. The noise also indicates problems with the blower assembly or burners. Cleaning everything and ensuring it works correctly will eliminate the sound and reduce the risk of costly problems in the future. 

Author

  • Jake Alexander

    Jake is a freelance writer from Pennsylvania who enjoys writing about science and sports. When he's not writing for Temperature Master, he can be found watching the NFL or playing basketball with his friends.

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