Is your furnace making loud noises all of the sudden? Every homeowner will experience this issue at some point or another.
Taking quick steps to remedy the problem early is key to maintaining a well-functioning HVAC system—and avoiding possible irreparable damages.
Most modern furnaces are designed to work as silently as possible while still producing the optimal amount of heat for your home.
If your furnace is making unusual sounds, it may indicate that something is wrong with the unit.
This article discusses the various reasons why furnaces become noisy and gives you solutions to each situation.
So, why is my furnace so loud?
There are several reasons why your furnace is making noises. Some of the most common causes are:
- A clogged air filter
- Small gaps in the ductwork
- Dirty burners
- Loose screws in the furnace
- Cracked heat exchanger
- Loose blower wheel
- Busted blower motor
Let’s take a closer look at each issue and learn how to fix them individually.
Reason #1: A Clogged Air Filter
The first reason for loud furnace noises is a dirty filter. Filters prevent dust, dirt, and other particles from entering the furnace.
Over time, all these particles can accumulate on the filter, obstructing proper airflow.
Filters with restricted airflow can be identified by a screeching or whistling noise coming from the furnace. One way to fix this problem is to replace the old filter with a new one.
How to change a furnace filter?
Furnace filters are easy and cheap to replace. Most homeowners can handle DIY furnace filter replacement.
Still, if the process confuses you, it’s best to call a professional HVAC technician to handle the issue for you.
Otherwise, you can perform the following steps to get the job done:
Step 1: Find out what size filter you need
Furnace filters come in various sizes. To identify the size of your furnace’s filter, you need to take it out and inspect it.
The furnace filter is typically located inside the furnace’s air return vent.
After removing the filter, take note of its size on a piece of paper or bring it with you when you buy a new filter.
Step 2: Mark the direction where the filter should be facing
You will find an arrow marking the right direction your filter should be facing when inside the furnace. Take note of the direction or get a marker and a sticky note to mark the location.
Step 3: Buy your furnace filter
Filters are available in most local hardware stores or appliance centers. You can also order them online, often at better prices.
Remember to double-check the size so it’s compatible with your furnace.
Step 4: Install the new filter
Once you have the new filter, you can proceed to replace your old filter. Follow the new filter’s markings to ensure it’s facing the right direction inside the furnace.
Step 5: Turn on your furnace
Turn on your furnace and check if it still makes whistling sounds. If it is, something else might be causing the furnace sounds.
Reason #2: Small gaps in the ductwork
Another reason for annoying furnace sounds is if your furnace ductwork has small holes or gaps in them.
Gaps in the ductwork can generate a whistling sound that can wake even the deepest sleeper. Most of the time, you can trace gaps back to the joint that connects your furnace to the ducts.
While DIY repairs for this type of issue are possible, we don’t recommend them. If you suspect small gaps or holes in your ductwork, call a professional HVAC technician immediately.
Reason #3: Dirty Gas Furnace Burner
Dirty burners are another reason for a noisy furnace. It’s typically characterized by a booming or banging noise, which is caused by a delayed ignition of the burner.
Furnace burners typically ignite immediately when in use. When there’s dirt blocking the burners, it can cause gas to build up inside, which creates a loud “bang” when it finally catches a flame.
How to know when it’s time to clean the furnace burner?
Besides furnace noises, several signs can indicate when your furnace burner needs cleaning. This includes:
- A yellow or orange flame
- Strange odors coming from the furnace
- Poor heat production
- Higher energy bill
- Lower indoor air quality
How to clean gas furnace burner?
Before you start cleaning your furnace burners, you need to gather the following materials:
- A power drill
- A small wrench
- Brass brush
- Flexible drill extension
- Compressed air
Perform the following steps once you have all your materials ready.
Step 1: Turn off the furnace
Turn off your furnace to avoid accidentally igniting the furnace while you’re cleaning.
Step 2: Remove access panels and locate the burner
Access panels come in various shapes and sizes, depending on the furnace. Some doors simply slide off while others will need to be unfastened using a wrench or a screwdriver.
Check your furnace manual to see how to remove your furnace’s access panels properly.
Some furnaces come with a burner box or metal casing that houses the burner. Find this container and open it. Take note of how the burner is placed inside. Photograph its placement for reference when you put the burner back later.
Step 3: Remove the burner from the container
Using a wrench or drill, remove the screws holding the burner in place. Gently take the burner out of its case and start cleaning.
Step 4: Brush the burner
Brush away any dirt or build-up on the burner using a small brass brush. Don’t forget to include the flame sensor to remove carbon deposits from its surface.
Blow compressed air on each end of the burner to dislodge any debris. Do the same thing with the flame sensor.
Step 5: Re-install the burner and run a blue test
Retrieve the pictures you took earlier to ensure you place the burner in the right way. Be careful not to force the burner into place; otherwise, you might damage the other components of the furnace.
Turn on your furnace and check for a blue flame. If the flame has finally turned blue instead of yellow, then your burner is clean.
Listen for more banging or booming noises. If you still hear furnace noises, then something else might be causing the issue.
Reason #4: Loose Screws in the Furnace
If your furnace begins to rattle, it typically means it has a loose screw somewhere. Examine your furnace and find where the screw might be. Use a screwdriver to tighten the screw back into place. This should get rid of the rattling noises and give you back a peaceful night’s sleep.
If the rattling continues, something else might be causing the issue.
Reason #5: Cracked heat exchanger
Furnace noises can also be caused by a cracked or broken heat exchanger. A heat exchanger can crack when heat builds up in the component due to improper airflow.
It’s important to immediately remedy the issue, as heat exchanger cracks can lead to carbon monoxide leaks. Long exposure to this clear gas can cause carbon monoxide poisoning.
A heat exchanger crack is a serious problem—it could mean you have a carbon monoxide leak. Keep an ear out for rattling noises and your carbon monoxide alarm. If the alarm goes off, get everyone out of the house and call a professional technician to fix your heat exchanger.
Reason #6: Loose Blower Wheel
The blower wheel ensures proper air circulation inside the furnace. If it becomes loose, it can bump against the blower’s shell, causing an annoying screeching or scraping noise.
If you hear a metal-against-metal sound, it could mean that your blower wheel has become loose. Contact a professional HVAC technician to take care of the issue pronto.
Reason #7: Busted Furnace Blower Motor
Another reason for loud furnace noises is a busted blower motor. The blower motor is what pushes warm air through the air ducts connected to your furnace. It needs to always be properly oiled; otherwise, it can lose its functionality and make screeching noises while in use.
If you notice screeching or scraping sounds coming from your unit, it could mean your blower motor has lost its lubrication.
To restore the proper flow of warm air in your air ducts, contact a professional technician to check the situation.
Professional Furnace Repair and Maintenance
Professional furnace repair and maintenance can help prevent issues like loud furnace noises. While it’s possible to perform DIY fixes for some HVAC problems, there are issues that need the expertise of a professional technician. If you notice rattling, scraping, loud booming, or popping noises from your furnace, you can rely on our technicians to fix it.
BelRed
At BelRed, we train our technicians to provide our clients with efficient and effective solutions. If you have a problem with your heating system, rest assured our professional technicians can help you solve the issue. Our services range from heat pump and AC repair to plumbing services.
Contact us today to learn more about our offers.
CALL (855) 345-6161
