Many parts of the world get uncomfortably cold during the winter, and it’s necessary to use another heating source to heat homes. While some houses have built-in fireplaces, others must rely on space heaters or a furnace to stay warm.
Modern furnaces excel in providing consistent, energy-efficient heat. However, that isn't to say they can't have significant issues. An excessively noisy furnace is one such common problem that homeowners encounter.
A furnace circulates heat throughout the house, but it can make a lot of noise in the process. When it's linked to a blower, the noise frequency skyrockets. People that use furnaces prefer to store them in basements for this reason.
The blissful silence you want to enjoy in your home can be ruined by overly loud noise from the furnace blower. If you are experiencing this issue, keep reading to find out how to quiet a noisy furnace blower using different at-home methods.
How To Quiet a Noisy Furnace Blower
Check the Lubricant Level
Your furnace blower could be making a lot of noise due to a lack of lubricant. Old model electric motors lack sealed bearings. Oil must be added to the oil ports at each end of the shaft often. If the shaft does not have oil ports, then do not oil it. This will simply remove the lubricant from the bearings.
Oil is definitely required for older blower wheels. Some older models may include grease cups that must be regularly filled with bearing grease. To get to them, you will have to remove the access cover. You can use 3-in-1 motor oil, which is designed to work with electric motors.
Check and Clean the Blower Fan
You would be surprised how much noise a filthy blower fan can make. The blower fan might become unbalanced and vibrate if there is a lot of debris on it. Debris accumulation also puts additional strain on the blower motor.
In this case, use a shop vac to remove dust and debris, then wipe the area around the blower fan with a clean cloth to remove any remaining dirt. Check to see that the blower fan is properly greased and free of obvious damage.
Examine the Blower Motor
The blower motor might also grind or make terrible noises if the bearings are worn out. Begin by inspecting the blower motor housing for evidence of abnormal wear and tear, such as metal particles.
Check that the blower motor fan is moving freely and without resistance by turning it. It's a good idea to oil all bearings with WD-40 or 3-in-1 oil if there's a lot of debris and dust. Most noise problems can be resolved with a combination of cleaning and oil.
If a damaged bearing is found, you should replace the furnace blower motor right away or contact a professional. Continuous use of a faulty blower motor can result in serious damage or a fire.
Examine the Blower Motor Capacitor
It's possible that the capacitor is failing if you hear a continuous screeching sound when the blower motor starts. The capacitor, like the capacitor in AC units, stores an electric charge that aids in the start-up of the blower motor. This is a simple part to replace. However, make sure you cut off the electricity and pay attention to the wiring before replacing it.
Check the Blower Motor Belt
Many quiet furnace blowers run on belts, much like a car's engine. Rattling noises might be caused by a dirty, misplaced, or slipping belt. The belt can fall off or even fall apart in a worst-case scenario.
Make sure the belt is clean and correctly aligned by wiping it down with a clean cloth. Remember to inspect the belt for signs of wear and tear. If the belt appears to be overly worn, it should be replaced.
Check the Draft Inducer Fan
The draft inducer fan, which is located near the heat exchanger, propels combustion gases into the flue pipe while pulling fresh air towards the burners. Bad bearings can cause a draft inducer fan to make a lot of noise.
If the fan motor's bearings are worn out, they should be replaced. Because of the location of the draft inducer fan, you might want to hire an HVAC professional to replace it.
Check the Fan Blades for Debris
Check the furnace blower for any evidence of debris buildup if you hear grinding noises coming from it. Grinding noises and vibrations might be caused by material stuck in the fan blades. Remove any debris that has accumulated on the fan blades with care.
Examine for Loose Screws
Sometimes all your furnace blower needs is a simple solution. Set screws and mount screws for blower fans can loosen with time. This can cause the blower wheel to rattle like a cage or the motor to tremble and bang. Check your furnace blower, and if you find any loose screws, tighten them with a screwdriver.
How To Quiet Duct Noise
Add Return Air Duct
From a distance, a furnace blower can produce a whistle tone. If you open the air filter door and see the noise level dropping, it means the blower isn't getting enough return air.
It's possible that it's creating a vacuum on the intake side instead of properly pushing air through the system. The noise is caused by a large pressure difference between the intake and output sides.
If you're certain this is the issue, you can lower the noise level by adding more return air ducts. You might require the assistance of a professional to replace the air ducts. A permeable filter can help improve furnace airflow.
Seams Must Be Sealed
When you hear a whistling sound coming from your air ducts, this is due to air escaping through the seams and joints. Aluminum duct tape is excellent for preventing air from escaping. Not only does it quiet the air ducts and the furnace blower, but it also enhances your overall energy efficiency.
Expand the Duct
The sheet metal that makes up much of the ductwork in your furnace can create noise from time to time. When the sheet metal is exposed to warm air from your furnace, it expands and shrinks as it cools. You'll periodically hear the ducts snap back into shape like a drum as this happens.
These are, once again, regular sounds. However, you should inspect your ducts to ensure that there are no loose or missing panels.
Insulate the Ducts
By transporting furnace noises from room to room, your furnace ducts operate as a sound superhighway. A little acoustic insulation placed over the ducts can help to reduce echoes and air rushes.
Sound insulating the ducts will provide you with more than just sound absorption. Depending on the type of insulation used, you can also reduce heat loss. This increases the overall efficiency of your furnace while lowering energy consumption, saving you money on your heating expenses.
Change Your Air Filters
Dust and other undesirable particles are trapped by furnace air filters, preventing them from entering the furnace. The more the furnace blower tries to pull air through the air filter, the more junk it collects. Your furnace may sound louder than usual due to a dirty air filter.
If this is the case, replace your air filter as soon as possible. Changing the air filter in your furnace on a regular basis helps to reduce noise while also reducing the stress on your furnace.
Certain air filters can be too restrictive for air to pass through and make your furnace blower work harder than usual. Air filters that have a MERV (Minimum Efficiency Reporting Value) rating of 7-12 can function efficiently without causing restrictions.
However, unless your furnace was expressly developed with high-rated air filters in mind, avoid using air filters with a MERV 13 rating or above.
How To Quiet Cabinet Noises
Soundproof the Cabinet
Most contemporary furnaces feature soundproofing material in the blower compartment, and new furnace engines and blower fans are quite quiet. The apparatus of older furnaces are frequently housed in metal boxes.
If your furnace features a metal box, we recommend lining the box with something like an automotive sound deadening mat, which is completely self-adhesive. This is important because screwing through the metal cabinet destroys the soundproofing scheme, and drilling into something vital like your fuel line could make matters much worse.
Soundproof the Basement Furnace Room
Most furnaces are placed in basements or similar separate rooms to separate the heating system from the living space.
Even though it’s in a separate room, you can often hear the noise of a loud furnace. Soundproofing your furnace or basement room is a simple fix for a quieter house.
You can start by framing the room, then soundproofing the walls and ceiling, drywalling, and finishing as needed. For both unfinished and finished basement rooms, there are also other realistic alternatives.
These include using soundproofing blankets on the walls and a soundproofing curtain over the doorway. Moving blankets will also suffice in this situation. The blankets will almost certainly need to be trimmed and taped around any plumbing fixtures, boxes, and electrical wires.
Soundproof the Main Floor of the Furnace Room
Furnace room floors usually have an impact noise problem. This is because the furnace is placed on the framing instead of a concrete floor. As a result, the ductwork and the framing transmit sound and vibrations.
After doing everything you can to quiet the blower fan, motor, and cabinet, you should try lifting the furnace high enough to get a sound and vibration-dampening product under the contact points.
The majority of furnace rooms on the main level are designed to take up as little space as possible. As a result, operating within them is at best a struggle. Plus, the walls are almost certainly covered with drywall or paneling. This leaves you with putting soundproofing blankets on the walls as your best bet.
If your house has an attic, you should also soundproof the ceiling to prevent noise from spreading around the house. Acoustic panels are fire-resistant and sound-absorbent. You can use double-sided mounting tape to attach them.
In some house designs, the cold air return for the furnace is located on the main floor and has a louvered door for this purpose. If your house design falls in this category, you shouldn't cover the door completely or with something really thick. This can disrupt the furnace's performance. You can try to cover some parts of the door to reduce noise while leaving enough space for cold air return.
For this method, take it slowly. Cover a little area from the top with a blanket and wait to see how the furnace functions. Once you're sure that everything is working correctly, you can keep adding until you've reached the maximum soundproofing capacity of the furnace.
You should not interfere with the louvered door if only a section of the door has louvers.
What To Do Before Checking or Making Any Repairs
Before checking any of these potential issues or making any repairs, there are a few important steps to follow.
- Turn off the furnace breaker.
- Turn the thermostat all the way down.
- Turn off the gas completely.
You have to be extremely careful while working with a furnace. Make sure to follow the steps above to avoid any potential disasters.
A noisy furnace blower is incredibly irritating. Plus, the constant noise could be a sign of underlying problems in the furnace that could cause it to break down in the near future.
The measures outlined above are there to help you quiet your furnace easily and efficiently while making sure that no harm is done to the furnace itself or your house. Regular furnace check-ins and cleanings will also help your furnace last longer.