Makeup Air and Kitchen Exhaust

Every home needs to have kitchen exhaust to remove cooking smells and smoke when cooking. An added benefit is it makes a home healthier by removing stale and smelly air.

When this happens, outdoor air seeks to replace this air by entering through cracks or intentional openings in the home’s envelope, known as makeup air.

Unitary Makeup Air System

New
Kitchen Muas 8 Muas 10 W Arrows 01

Exhaust fan

The fan exhausts the amount of air equal to the makeup air.

Silencer

Sound attenuation silencer for circular ducts. The silencer effectively reduces noise in the duct.

Makeup Air System (MUAS)

The MUAS is a powered, fresh air supply system that’s ideal to balance the outgoing vented air from a 400+ CFM range hood required by the IRC.

Key Benefits

Discover our New Makeup Air System

Efficient and Streamlined Installation

The MUAS features a unitary design that integrates a MERV11 filter, motorized impeller, and controller into a single compact 1” isolated cabinet. This all-in-one system simplifies installation and reduces setup time, fitting conveniently within a 24" on-center layout.

Enhanced Performance

Every home requires effective kitchen exhaust to remove cooking smells and smoke. The MUAS not only fulfills this need but also enhances overall air quality by eliminating stale and smelly air. This process allows outdoor air to replace the expelled air through the home’s envelope, ensuring a healthier and more comfortable living space.

Flexible and Versatile

The MUAS is available in two sizes to meet various airflow needs: MUAS 8 for 8" ducts and MUAS 10 for 10" ducts. With airflows of 630 cfm and 1050 cfm respectively at 0.4 in.wg., it provides versatile options for different home ventilation requirements.

Code Compliant

Designed to meet building codes such as IRC M1503, the MUAS ensures balanced airflow and prevents harmful back-drafting, promoting a healthier indoor environment.

Installation Made Easy

Discover our New Makeup Air System

Simple Unboxing

Includes the main unit, mounting brackets, and shut off damper.

Streamlined Design

Reduces installation complexity with all components built into a single unit.

Modular Makeup Air System

Legacy

Exhaust Fan

The fan exhausts the amount of air equal to the makeup air.

Silencer

Sound attenuation silencer for circular ducts. The silencer effectively reduces noise in the duct.

Duct Heater (Optional)

The Makeup Air Heater automatically varies its heat output to deliver air at the temperature set point.

Makeup Air System (MUAS)

The MUAS is a powered, fresh air supply system that’s ideal to balance the outgoing vented air from a 400+ CFM range hood required by the IRC. 

Makeup air systems represent a calculated balance that ensures a controlled environment, code compliance, safety, and energy efficiency.

Christina Gomes
Christina Gomes
Project Engineer

Why Do You Need a Makeup Air System?

If the kitchen exhaust system exhausts more than 400 CFM, the International Residential Code (IRC) requires mechanical or passive systems to provide makeup air back into the home. 

Even if the exhaust system is only capable of removing 350 CFM of air, it is a good idea to have a makeup air system in place to keep the household safe from backdrafting and the temperature regulated. 

Regulations and Factors

Important to know
  • UL507 Requires products undergo many performance tests, construction requirements, and marking regulations to help keep electric fans safe. 

  • International Residential Code (IRC) M1503.6 States that where fuel-burning appliances are present and exhaust systems exceed 400 CFM, makeup air must be provided at a rate equivalent to the exhaust air rate.

  • IRC M1503.6.1 States makeup air must be discharged in the same room the exhaust system is located in or into rooms or duct systems connected to the room containing the exhaust system.

  • IRC M1503.6.2 States that makeup air dampers must either be gravity dampers or electrically operated dampers that automatically opens when the exhaust system operates.

  • IRC M1505.2 States to not discharge air from kitchens into areas inside the building.

  • IRC M1505.3 Requires mechanical ventilation fans be listed and labeled providing the minimum airflow within AMCA 210 or HVI916.

  • Compliance and Efficiency Adhering to codes ensures safety and minimizes costs through energy-efficient solutions.

  • Temperature and Humidity Control Integrating a duct heater in the makeup air system helps temper cold air, minimizing condensation.

  • Customizable The MUAS allows for linear or flexible snake-like configurations with sufficient ductwork while an exhaust system can be installed in an exterior wall or in the ceiling directly above the food prep station.

  • Quiet The remote mounting location of the exhaust system ensures noise is kept away from the living space.

  • IAQ Kitchen exhaust, combined with a mechanical makeup air system, maintains balanced indoor air pressure during fan operation, ensuring safe removal of smoke and grease, thus enhancing indoor air quality.

For kitchens equipped with cooking appliances, ensuring makeup air enters the home is essential. While older homes typically rely on natural infiltration to prevent backdrafting, newer, more energy-efficient and air-tight constructions necessitate mechanical or passive methods to maintain balanced air and prevent backdrafting. This requirement applies to remodeled kitchens as well.

What to Know?

How to size the unit?

Match the exhaust fan capability with either the MUAS 750 or the MUAS 1200. If the CFM is 750 or less, use the MUAS 750. If it is more than 750, opt for the MUAS 1200 to match that outgoing air. 

What about exhaust?

The rule of thumb for range hood fan size is “for every 12” of stove width, the exhaust fan must be able to move 100 CFM of air.” 

Do I need a silencer?

The LD silencer reduces the "perceived" noise of a kitchen ventilation system by 50–60%. This is particularly important with range hoods where the airflow rate is generally high (300+ cfm). 

Installation

Best practices

Installed in an uninsulated environment?

Yes, however, try to avoid installing the makeup air system and the supply air duct work directly above or less than 2 feet to any furnace or its supply plenum, boiler, water tank or any heat producing appliances. Remember to insulate the ductwork to the R value required for your area.  

What if they have a fireplace?

A makeup air system is safe to operate with a fireplace in use and should be installed to prevent backdrafting. 

Discovery Questions

Good to Know

Can I use a Makeup Air System with multiple exhaust fans?

The MUAS will not replace the air exhausted from any other system besides the kitchen exhaust system. The MUAS is interlocked with the kitchen exhaust system.

What is the best location for an interior register to bring the fresh air into the home?

Fantech suggests installing the supply air register as close to the kitchen exhaust range hood as possible.

Should you use a heater with a MUAS?

If you are in an area that experiences cold weather in the winter time, you will want to have an additional MUAH heater to temper the air coming into your home. 

Can you install a MUAS in a vertical position?

Yes. Due to its component-based, field-assembled nature, the Fantech MUAS offers flexibility in the installation process as far as location and point of orientation are concerned. However, Fantech recommends that the installation location be suitable for periodic inspection and maintenance. The MUAS does not require installing the individual system components in a linear (straight line) arrangement. 

Can the components be installed with a 90 degree bend?

Yes, you can split the components into segments to support tight spaces. Be mindful of the location of the heater when altering the air path through the device. Install the components a minimum of 24 inches before and after the heater to ensure linear airflow across the elements. Non-linear air flow can create pockets of low air that can cause the element to overheat and shorten the elements life.

How often should the filter be changed?

At a minimum, Fantech recommends you inspect the filter every 2–3 months. Once you have a better understanding of how the air quality affects the MUAS over a longer period, you may only have to inspect your filter every 6 months.

Modern, loft style community kitchen

Community Kitchen

Community Kitchens are increasingly popular for larger gatherings in multi-family residential projects. They require powerful exhaust systems and makeup air systems that don't disrupt communal gatherings with noise.


Food Prep Area

Kitchen exhaust

Using an exhaust fan to remove cooking odors is an effective method for improving IAQ. However, in scenarios with large kitchens and extensive food prep stations, addressing persistent smells like cut onions or slow cooker aromas can be a challenge. In such cases, a straightforward solution is to install an exhaust duct connected to an inline fan to effectively eliminate these odors.

Installing an exhaust fan specifically over the food prep area is a great way to address a common pain point for our customers. It tackles those lingering food odors before they spread throughout the house, making kitchens more enjoyable.

Picture of Ivan on a blue background
Ivan Daza
Project Manager

How Does the Design Work?

A simple exhaust duct concealed in a wall or cabinet connected to an inline fan in the attic controls a plethora of food prep odors.

Another idea is using an exterior wall fan connected with rigid duct and an intake port directly above the food prep station.

Either way, the fan gets activated by pressing a push button timer for a desired time interval between 20 and 60 minutes. To protect from air backdrafting through the inline fan design, a vent louver should be used to protect against infiltration or loss of tempered air.

What to Know?

Kitchen Exhaust

What accessories are needed?

A push button timer is essential for this design. This allows the user to active the system only when it is needed. Duct work and mounting clamps are other accessories needed.

Do I need a Silencer?

Because of the remote mounting location of the fan, a silencer wouldn’t be needed. However, if you think your customer would find this application to be too noisy, a silencer would be a great choice to reduce vibrations and subsequently reduce noise. 

FD

Make sure the food prep area gets the proper amount of ventilation when needed the most. The timer utilizes 10, 20, 30 and 60 minute timed operation.

Learn from Our Pro

Video

Discover the fundamentals of Fantech's Makeup Air Systems with insights from our expert, Mark Wald. This concise video provides essential information in under one minute.

See Successful Projects with MUAS

Learn About Other Solutions for Single Family Residential Projects