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Air Vents FAQ

This section covers basic information about air vents selections and characteristics that would assist you to select the proper product for your projects.


Do you make custom air grilles, register, & diffusers (GRD)

  • Yes, we do make customized GRD based on our original product in conjunction with drawings provided by the client. For larger projects we can provide product development service tailored to the project specifications.

Do you offer performance data for your products?

  • Majority of the basic product performance information should be available online or on our product page. Please contact us if you require additional information in regards to our standard product performance data. Our product data are collected in accordance to ASHRAE Standard 70 “Method of Testing the Performance of Air Outlets and Air Inlets (ANSI approved)” or ADC1062R4 (ADC1062:GRD-84).

Do you offer plenums for your products?

  • Yes, our plenums are mostly custom made and they are constructed in accordance to the material specifications of the following standards:

Canada & US
Sheet Metal and Air Conditioning Contractors' National Association
SMACNA –– HVAC Duct Construction Standards
The Building Engineering Services Association
BESA” – DW/144 Spec for Sheet Metal Ductwork
Custom Plenum

What are air grilles, register, & diffusers (GRD)

Although many people conceptionally think they are the same, in reality, they are not. In fact, each of them plays a different role that would impact the thermal comfort and air quality in the air-conditioned space.
  • Grilles – Commonly it is a piece of static (no moving parts) hardware that allows air to pass through
  • Registers – Usually contains one or more moving components that allows users to adjust the direction of air flow and air volume
  • Diffusers – Disperse air into a space in an air pattern for optimized airflow circulation
    To be more specific, there are 7 classes of supply air outlets for different applications:
      • High side wall grilles
      • High side wall linear grilles
      • Low side wall grilles
      • Baseboard
      • Floor grilles
      • Ceiling Diffusers
      • Ceiling linear slot diffusers


    How do I choose air grilles, register, & diffusers (GRD)? Are there any product performance attributes?

    Even though the product appearance might have influenced the initial choice, all HVAC engineers and technicians would look for the following basic attributes when it comes to GRD selections:

    Air Flow Rate (L/s or CFM) The amount of air flow in reference to time
    Static Pressure (Pa or In.Wg) The amount of air pressure build up in the plenum
    Throw (m or ft) The distance/range that air pattern would cover in an area
    Acoustic Level (NC or dBA) Noise level generated by the vent w.r.t. the air flow rate

             For Example:

    Performance Data
    For some projectsjust by reading the air flow rate (CFM) alone would not be sufficient because the actual air vent CFM could actually be less than the rated value. This is because the air supply static pressure of the project site is not fully compatible with the manufactures’ tested parameters. If this happens then you would end up with a less efficient HVAC system.


    My air vent is noisy or whistling, why is that?

    There are many contributing factors to this but the No.1 cause could be the vent cover is restricting the air flow at their designed flow rate. Consider how a person blows a whistle; the whistle generates noise by pushing a gush of air into a small mouthpiece with a small opening at the front. This is what could be happening with a noisy air vent as the vent opening is simply too small for the air to pass through!
    Without tempering with your HVAC current settings/configuration, the feasible option is to replace with an adequate air vent under professional advice.
    Another possible factor for noisy vent could be the material quality and material thickness used on the product. Thinner and weaker materials are susceptible to unwanted noise due to mechanical vibrations, noise transmissions and weaker structural integrity due to weaker welding joints.

    Do you make Plenum Reducers (transform fittings)?

    Yes, we can also offer fittings for our plenums if the project requires it. However, we usually suggest the customer to use the exact fitting sizes/shapes on their plenums when placing an order with us.