Air Vents FAQ - Flo-Matrix HVAC

This section covers basic information about air vents selections and characteristics that would assist you to select the proper product for your projects. For a more in-depth learning experience, please head to our HVAC Insights corner. 

General HVAC Vent Questions

1. What is a linear slot diffuser?

2. Are linear slot diffusers suitable for residential homes?

3. How do I measure my air vent opening?

4. How do I choose the right HVAC diffuser?

Choosing the Right Product

1. What is the difference between 19mm and 25mm slot diffusers?

2. How many slots should I choose?

3. What performance attributes should I consider?

4. Do you provide product performance data?

Installation & Custom Solutions

1. Do linear slot diffusers require a plenum box?

2. Do you offer plenum boxes for your products?

3. Do you make custom plenums and reducers?

4. Do you make custom air grilles, registers, and diffusers?

Troubleshooting

1. Why is my air vent noisy or whistling?

2. Can replacing my diffuser improve airflow?

3. Can aluminum HVAC diffusers be painted?

Orders & Projects

1. Do you provide project pricing?

2. Do you offer contractor or volume discounts?

3. Do you ship to the USA?

General HVAC Vent Questions

What is a linear slot diffuser?

A linear slot diffuser is a modern HVAC air outlet designed to distribute conditioned air through one or more narrow continuous openings. Unlike traditional square or rectangular grilles, linear slot diffusers provide a clean, architectural appearance while maintaining effective airflow distribution.

Linear slot diffusers are commonly used in residential custom homes, offices, commercial spaces, and modern interior designs where a minimal ceiling or wall appearance is desired.

Flo-Matrix linear slot diffusers are available in different slot widths, lengths, and slot configurations to accommodate various airflow requirements and design preferences.

Want to learn more?

Read our in-depth guide, Linear Slot Diffusers: The Smart Choice for Modern HVAC Systems, to learn more about the benefits, applications, airflow performance, and design advantages of linear slot diffusers.

Are linear slot diffusers suitable for residential homes?

Yes. Linear slot diffusers are increasingly popular in modern residential construction, renovations, and custom homes.

They are commonly installed in:

Living rooms
Kitchens
Open-concept areas
Home offices
Basements
Bedrooms
Custom architectural ceilings

Compared with traditional ceiling registers, linear slot diffusers provide a cleaner appearance by blending more naturally with modern interior designs.

Proper sizing and airflow selection are important to ensure the diffuser performs correctly for the HVAC system.

How do I measure my air vent opening for a replacement?

To select the correct replacement air grille, register, or diffuser, measure the duct opening size rather than the outside dimensions of your existing vent cover.

For the most accurate measurement:

1. Remove the existing vent cover.
2. Measure the width and length of the opening where the vent connects to the duct.
3. Confirm the required mounting style and available installation space.
4. Compare your measurements with the product specifications.

For custom applications, provide your required dimensions, drawings, or photos, and our team can help determine the best solution.

Product Selection Questions

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

Selecting the correct HVAC air outlet depends on both appearance and performance requirements.

Important factors to consider include:

• Airflow Capacity
  The diffuser must be properly sized to handle the required airflow volume for the space.
• Pressure Loss
  Pressure loss indicates how much resistance the air encounters as it passes through the diffuser. Lower pressure loss generally helps maintain efficient HVAC system performance.
• Air Distribution Pattern
  Different diffuser designs provide different airflow directions and throw patterns. The correct selection depends on ceiling height, room layout, and installation location.
• Noise Level
  A properly sized diffuser helps reduce unwanted airflow noise caused by excessive air velocity or restriction.
• Appearance
  For architectural applications, many customers choose linear slot diffusers because they provide a sleek, low-profile appearance compared with traditional vents.

         For Example:

What is the difference between 19mm and 25mm linear slot diffusers?

The main difference between 19mm and 25mm linear slot diffusers is the width of the visible air opening, which influences both the architectural appearance and airflow capacity.

19mm Linear Slot Diffusers

• Narrower, more discreet appearance
• Ideal for minimalist architectural designs
• Suitable for many residential and light commercial applications

25mm Linear Slot Diffusers

• Wider opening with increased free area for higher airflow capacity
• Offers a bolder, contemporary architectural appearance
• Becoming increasingly popular in modern custom homes and commercial buildings
• A preferred choice for many architects, designers, and HVAC professionals seeking a balance of aesthetics and performance

Both slot widths are engineered to deliver excellent airflow performance when properly selected. The best choice depends on your HVAC system's airflow requirements, room size, design preferences, and project specifications. If you're unsure which slot width is right for your application, our team can help you select the most suitable option.

Want to learn more?

Read our in-depth guide: 19mm vs. 25mm Linear Slot Diffusers: A Quick Guide for HVAC Pros & Homeowners for a detailed comparison of airflow, noise, performance, aesthetics, and applications.

How many slots should I choose for my linear diffuser?

The number of slots determines the available airflow capacity and appearance of the diffuser.

Single Slot Diffusers

• Minimal, clean architectural appearance
• Suitable for lower airflow applications

Double Slot Diffusers

• Provides increased airflow capacity
• A common choice for residential and commercial applications

Triple Slot Diffusers

• Designed for applications requiring greater airflow capacity
• Suitable for larger rooms or higher airflow requirements

The correct number of slots should be selected based on HVAC design requirements rather than appearance alone.

Do your products come with performance data?

Yes. Most of our standard performance data is available on our individual product pages. If you need additional information, please contact us directly. All our data is tested and collected in compliance with industry standards, primarily ASHRAE Standard 70 "Method of Testing the Performance of Air Outlets and Air Inlets (ANSI approved)”or ADC1062R4 (ADC1062:GRD-84).

Installation & Custom Solutions

Do linear slot diffusers require a plenum box?

A plenum box is recommended for many linear slot diffuser installations because it helps distribute airflow evenly across the entire diffuser length.

A properly designed plenum can help:

• Improve airflow distribution
• Reduce uneven air delivery
• Provide easier duct connection
• Support proper diffuser performance

Whether a plenum is required depends on the installation design, diffuser length, airflow requirements, and HVAC system layout.

Do you offer plenums for your products?

Yes, we do. Our plenums are typically custom-made to ensure a perfect fit for your specific application. They are constructed to meet material specifications from key industry standards, including the following: 

Please contact our team with your project details, and we can provide a solution that meets your requirements.

Do you make Plenum Reducers (transform fittings)?

Yes. We manufacture custom plenum reducers and transform fittings for HVAC applications where the duct connection size does not match the diffuser or plenum opening.

Custom reducers can help connect different duct dimensions while maintaining proper airflow transition.

Contact us with your required dimensions or drawings for a custom solution.

Do you make custom air grilles, registers, and diffusers (GRD)?

Yes. Flo-Matrix HVAC specializes in custom air grilles, registers, diffusers, and HVAC accessories.

Custom products are available for applications requiring:

• Non-standard dimensions
• Specific finishes
• Unique installation requirements
• Architectural design considerations

Whether you are working on a custom home, renovation, or commercial project, we can help develop a solution based on your requirements.

Looking for a custom HVAC solution?

See our custom HVAC grille and vent cover projects to explore examples of recent custom projects and learn more about our customization capabilities, including custom linear bar grilles, perforated vent covers, corner fittings, and other specialized HVAC solutions.

Troubleshooting Questions

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

The most common cause of a whistling vent is restricted airflow. Think of it like blowing a whistle: a high-velocity stream of air forced through a small opening creates noise. If your vent's opening is too small for the system's airflow (CFM), it will produce a similar whistling sound.

Without altering your HVAC settings, the most effective solution is to replace the vent with a larger, more appropriately sized model. We strongly recommend consulting an HVAC professional to diagnose the issue and select the right product for your system.

Another potential cause is the vent's construction. Products made from thinner, less rigid materials are more prone to vibration and noise transmission, which can also lead to rattling or buzzing sounds.

Can replacing my air vent improve airflow?

Replacing an air vent may improve airflow if the existing grille or diffuser is restrictive, damaged, or incorrectly sized.

However, airflow performance depends on the entire HVAC system, including:

• Duct design
• Fan capacity
• Static pressure
• Air balancing
• Diffuser selection

A properly selected diffuser can help distribute air more effectively throughout the room.

Can aluminum HVAC diffusers be painted?

Yes. Aluminum HVAC diffusers can be painted to match surrounding ceilings, walls, or architectural finishes.

For best results:

1. Clean and prepare the aluminum surface.
2. Use a compatible primer if required.
3. Apply a suitable paint designed for metal surfaces.

Painting may affect the factory finish, so proper preparation is important.

Orders & Project Questions

Do you provide project pricing?

Yes, we do! Our project pricing depends on several factors—primarily the quantity, as well as the specific requirements of your project. 

To get an accurate and tailored quote, please fill out our Request a Quote form, and our team will get back to you with detailed pricing based on your needs.

Do you offer quantity discounts for builders and contractors?

Yes. We work with builders, contractors, HVAC professionals, and project customers requiring multiple units.

Discount availability depends on product type, quantity, and project requirements.

Contact us with your order details for a customized quote.

Do you ship to the United States?

Yes. Flo-Matrix HVAC ships products to customers throughout the United States.

Due to recent changes affecting cross-border shipments, USA orders may require additional processing depending on product type and order requirements. Contact our team for assistance with USA orders.

For more information about ordering, shipping options, duties, tariffs, and the current process for USA customers, please visit our Shipping to the USA guide.

If you have any questions or would like to place an order, our team is happy to assist with your project requirements.