Basically you have to cut open the drywall where the ducts connect to each other. Then you have to make sure that they're straight, put a sheet metal screw in them, wrap it in aluminum tape, then get a piece of metal that wedges between the studs and secure the duct to it. This will stop the popping sound.
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.
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.
It sounds like expansion/contraction. If the furnace is oversized for the building, put a smaller variable speed one in so it doesn't cycle so much or run as hot, if it's hydronic, then lower the boiler temperature to what is needed to heat to reduce expansion/contraction.
Common causes of a knocking noise from a heat pump include frozen outdoor coils, an unbalanced indoor fan, loose parts rattling, and compressor damage. The icing on coils forces the unit to work harder, causing vibration. Fan imbalances, loose parts, and internal compressor failures can also create knocking sounds.
Placing small pieces of foam near pipes that travel through wooden supports will prevent banging or other bumping sounds. If this does not fix the issue, seek professional help by hiring residential heating services. You don't have to live with heating pipes that bump and bang all night.
It is best to place the Duct Silencer within 2 - 4 feet of the blower / ventilator for maximum noise reduction.
Lining the interior of your ductwork acts as a silencer. It adds insulation to make the system more efficient while diminishing sound. Using heat-resistant acoustic foam in the interior of your ducts is a low-cost way to decrease resonance. The foam absorbs sound energy and stops it from moving into other rooms.
Vent silencers are mounted after relief valves to reduce noise pollution to a bearable level. Relief valves are commonly used in i.e. power stations, as well as chemical, petrochemical and other similar plants.
If the pipe is secure and simply close to a wall, joist or other pipe, consider putting a small amount of cloth, foam or felt between the wall and pipe to remove the vibration. For pipes that have come loose, it can be much more difficult, especially if they're beneath the floorboards.
HVAC dampers are usually inside your ducts, close to the main air handler. You can find the dampers by looking at the outside of your ducts for a red switch on the exterior. If you can't find the HVAC dampers installed near the air handler, refer to your HVAC system's blueprint to locate them.
As temperatures rise, your air ducts' metal parts heat up. These parts will then move around, producing a knocking sound in furnace vents.
WHY ARE MY AIR DUCTS POPPING AND BANGING? One of the main causes for these loud noises are differences in pressure between the supply and return ducts. Another common cause is expansion and contraction due to changes in temperature.
Air duct disinfectant fog, or air duct sanitizer, is an antibacterial spray. Using special technology, it is applied by an AC technician throughout your air ducts to help reduce the growth of and eliminate mold, fungi, and bacteria.
Knocking sounds after it's turned off means there's a lot of uneven air pressure built up inside the unit. The first thing to do is pull off the cover and clean up any gunk or moving parts, probably clean or change the filter.
– 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.
An HVAC duct silencer is specifically engineered to reduce airborne noise carried along ducts or produced by enclosures. You'll also find these silencers described as sound attenuators when they are used in industrial settings.
Insulate Your Ducts
Insulating your ductwork will help dampen sounds echoing throughout your home. The insulation will also help retain heat, reducing the fluctuation between hot and cold ductwork. A more constant temperature will lead to fewer pops due to oil canning.
They take advantage of the principles of sound waves and the properties of materials to diffuse the noise. Sounds, just like light, are waves. When a sound wave hits an object, it's either absorbed, reflected, or transmitted. Duct fan silencers are designed to absorb these waves, significantly reducing the noise level.
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.
4a. 4b. For maximum performance and minimum noise, the best location to install your In-Line Duct Fan™ is 6 - 10 feet from the register you wish to boost air to.
What causes plumbing pipes to make a banging noise? If you hear a vibrating, banging or pounding noise when taps are turned on or off it's usually due to hydraulic shock in your plumbing pipework. Hydraulic shock is more commonly known as “water hammer”. The banging noise you hear is the result of vibrations in pipes.
If you hear similar clanging or loud banging noise in the walls, it can be a sign of clogs or air pressure in the system called a water hammer. If you don't resolve the problem, it can cause damage to the pipes, so consult a professional.