Dirty/Clogged/Old Filter If you don't change the air filter every 90 days, it can become clogged with dust and debris. A clogged filter can cause a high-pitched whistling, loud thumping, or buzzing sound.
Insulate the Vent: Use acoustic insulation or foam tape around the edges of the vent cover to dampen sound. This can help reduce vibrations and noise. Adjust the Airflow: If possible, adjust the airflow using dampers. Reducing airflow can sometimes decrease noise levels.
A whistling or roaring sound from a supply air vent could mean the vent has either too much air flowing through it or the volume damper inside the vent is partially closed restricting the normal airflow. Homeowners often close vents in empty rooms so they don't spend money to heat or cool unoccupied space.
In our case, the noise (clicking, tapping, thumping sounds) is caused by the continuous contraction and expansion of the metal ductwork. (heat expands; cold contracts) When warm forced air flows through the metal duct work, it will cause some expansion. And when it begins to cool a little, it will begin to contract.
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.
Loose or Unsecured Parts: Over time, components within your air conditioner can become loose due to regular wear and tear. When these parts move around, they can create banging noises as the unit turns off and on. Duct Expansion and Contraction: Your ductwork can expand and contract with temperature changes.
Steps to soundproof ductwork include changing the structure of the ductwork, lining the interior with sound absorption, creating a soundproof barrier for the exterior, and adding baffles for soundproofing inside the air vents.
CLEAN, SEAL, AND INSULATE DUCTWORK
While it may cost some money, the most effective solution short of replacing your entire duct system is to clean, seal, and insulate the ductwork. This will reduce pressure differences and soften the effects of any expanding and contracting metal ducts.
How to tell if the vent pipe is clogged? Common signs of a clog you can look for include slow-draining sinks and toilets, foul smells lingering in your home, or a gurgling sound in your drains.
Tapping in the ear sometimes suggested by the brain
Sometimes the brain fools us. For example, it is able to produce sounds that we perceive in the ear - even if there is no actual sound source. So our brain can also fake a knocking in the ear.
Signs of an air duct clog include: One room in your house is hotter than all the others. Dirty air coming from vents. Unusual spikes in electric bills.
Experts advise having your air ducts cleaned every 2 to 3 years to prevent many maintenance and health problems before they start. However, homes with pets or children with allergies should have their air ducts professionally cleaned more frequently than the recommended average.
It's normal to hear a low humming sound as air moves through your vents. Most of the time, you probably won't even notice it. However, if that sound becomes disruptive or if you hear more concerning noises (such as rattling, clicking, banging, hissing, or grinding), there might be a problem with your HVAC system.
Most often, it's your home's plumbing system. It may be due to fluctuating water pressure issues, loose plumbing pipes, or a faulty valve. To help find the problem and solve it, the first thing you need to do is take note when you hear the banging noises.
When ducts are too small, it can create a buildup of pressure in the system, which results in a clicking or popping sound. These noises can occur when the heating or cooling unit turns on or off, and sometimes persist throughout the cycle of the HVAC system.
You should be accustomed to the sound of your HVAC system running. A low hum or the sound of blowing air is normal. If your air vents suddenly become very noisy and distracting, it's often a sign of a more serious issue. Depending on the problem, there may be an easy or more complicated fix requiring a professional.
Inside your air ducts, two processes occur—contraction and expansion. As temperatures rise, your air ducts' metal parts heat up. These parts will then move around, producing a knocking sound in furnace vents. Fortunately, this is entirely normal and generally doesn't signal an issue.
Insulate Your Ductwork
If your ductwork isn't properly insulated or doesn't have insulation, add insulation to duct runs in the basement or attic. The insulation should be formed and designed to insulate ducts. The insulating material will muffle loud noises from within and it can improve energy efficiency as well.
– Air Duct Problems: Rattling, vibrating, knocking/banging, or whistling sounds coming from your HVAC system usually mean that your ductwork has something loose, a hole, or disconnected joints, amongst other things. If your HVAC system is making new loud noises when running, there could be an issue with your ductwork.
The duct silencers enable maintaining proper acoustic parameters in the rooms – even reducing noise in the rooms which require a high degree of acoustic comforts, such as e.g. sleeping rooms or reading rooms. The noise can be generated not only by the flow of air through the ducts.
Homeowners often report that there are popping and banging noises within their ducts. These usually happen in short bursts. They are caused by the heat- or cold-related expansion and contraction that occurs at the duct walls as the temperatures inside of the HVAC air ducts rise and fall.