How to reduce Plastic diffuser & grille noise
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  • Jimmy at
  • November 07, 2022

Plastic diffuser & grille identifies and resolves noise issues


Because many clients are used to their noise systems, they will benefit from you asking questions.



Ask questions like "Which room is the noisiest" and you'll get more noise-canceling opportunities than ever before. Here are some common causes of airflow noise and typical solutions you can offer.


Plastic diffuser & grille

Plastic diffuser & grille Excessive airflow


The most common cause of plastic diffuser & grille noise is excessive airflow. Research on Plastic diffusers & grilles confirms that noise levels increase as more air passes through Plastic diffusers & grille.



Solution - You have two options. If there is too much airflow in the room, you can reduce the airflow through the grill or increase the size of the duct and plastic diffuser.



If the airflow in the room is excessive compared to what is required, install at least 5 duct diameter balanced dampers in front of the plastic diffuser. Close the damper until the desired amount of air is delivered into the room. Tested to verify delivered airflow and noise reduction.



If the room has less airflow than needed and is louder, usually this means that the Plastic diffuser or grille may be undersized. Increase grill or duct size to match desired room airflow.



If the room has less airflow than needed and is louder, usually this means that the Plastic diffuser or grille may be undersized. Increase grill or duct size to match desired room airflow.



restrictive grille


Return grilles and return ducts are often undersized. This creates high-speed noise in grilles and ducts.



Solution - Since most are undersized, installing additional return ducts in another area of the building is usually your best option. This will also address the lack of airflow in the system by reducing the total external static pressure. Need to find a plumbing path to another room or hallway.



If access through the building prohibits the installation of additional return air ducts, check to see if the return air grille can be oversized near the equipment. Return air noise is usually caused by ventilators located in hallways, the return air ductwork is an open building cavity to which a return air grille is screwed. If there are no other channels, another grating can be cut into the back or side of the return cavity.