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  • Shawn Anderson

From Hoods to Fans: Understanding a Commercial Kitchen Exhaust System

Updated: Oct 30, 2023

The commercial kitchen exhaust system is an important component in the design and function of any professional kitchen. The exhaust system is responsible for removing smoke, grease, and odors from the kitchen, keeping both the kitchen staff and customers safe and comfortable. Understanding the various parts of a kitchen exhaust system is key to ensuring that the system runs safely and efficiently. In this blog post, we’ll take a look at the different components of a commercial kitchen exhaust system, from hoods and ducts to fans and filters.

What is a commercial kitchen exhaust system?

A commercial kitchen exhaust system is a vital component in any commercial kitchen. It is designed to remove grease, smoke, heat, and other harmful airborne contaminants from the cooking area and expel them outside. The system consists of a range hood, ductwork, fan, exhaust stack, make-up air unit, and a fire suppression system. Together, these components work to keep the air inside the kitchen clean, prevent the build-up of harmful fumes and vapors, and reduce the risk of fire hazards.

A properly functioning commercial kitchen exhaust system is essential for the safety and comfort of your kitchen staff and customers. Without one, your kitchen could quickly become a hot and stuffy environment, causing health and safety hazards. Furthermore, a lack of an exhaust system can lead to the accumulation of grease on kitchen surfaces, increasing the risk of fire. That's why installing a commercial kitchen exhaust system is not only mandatory by law but also essential for the efficient operation of your commercial kitchen.

Why are commercial kitchen exhaust systems necessary?

Commercial kitchen exhaust systems play a crucial role in keeping the kitchen environment safe and healthy. Cooking produces a significant amount of smoke, steam, and grease-laden vapors that can harm the kitchen staff and customers if not removed efficiently. A commercial kitchen exhaust system ensures that these harmful pollutants are removed from the air, providing a safe and comfortable working environment.

Additionally, kitchen exhaust systems are also necessary for maintaining the structural integrity of the building. Over time, grease-laden vapors can accumulate on surfaces and increase the risk of fire. The exhaust system effectively removes these vapors and reduces the likelihood of fire. Not only does this help protect the kitchen staff and customers, but it also protects the business and property.

Moreover, a properly functioning kitchen exhaust system also helps to improve the overall quality of the food being prepared. A system that is working well removes cooking odors and stale air, allowing the food to retain its natural aroma and taste.

Overall, a commercial kitchen exhaust system is a necessary investment for any commercial kitchen. Not only does it ensure a safe and healthy environment for employees and customers, but it also protects the business from potential hazards and improves the overall quality of the food.

How does a commercial kitchen exhaust system work?

A commercial kitchen exhaust system is designed to remove heat, smoke, and grease-laden vapors from the cooking area. These systems work by creating negative pressure within the kitchen hood and ductwork, which allows for the extraction of hot air and smoke outside of the building.

The exhaust fan is responsible for pulling air through the hood and into the ductwork, which is designed to transport the air outside. As air is pulled through the hood, the filters remove any grease particles from the exhaust stream.

Once the air reaches the exhaust stack, it is released into the atmosphere. In some cases, the exhaust air may be treated to remove pollutants before being released.

It’s important to note that a commercial kitchen exhaust system requires a balance of intake and exhaust air to function properly. The amount of air being removed from the kitchen must be replaced by an equal amount of fresh air being brought into the space. This is achieved through the use of a make-up air unit, which replaces the exhausted air with fresh, clean air.

Overall, a commercial kitchen exhaust system is a critical component of any foodservice establishment. Properly functioning systems are essential for maintaining a safe and healthy working environment for staff and customers alike.

The function of a commercial kitchen exhaust system

Running a successful commercial kitchen involves much more than simply cooking and serving food. There are many important safety considerations to keep in mind, one of which is maintaining a properly functioning kitchen exhaust system.

The primary function of a commercial kitchen exhaust system is to remove harmful contaminants from the air that are generated during the cooking process. This includes heat, smoke, steam, and grease vapors. If left unaddressed, these contaminants can build up over time and create a hazardous work environment for kitchen staff, not to mention impact the cleanliness of the facility.

Moreover, local regulations often require commercial kitchens to have an exhaust system in place, making it a legal requirement for running a restaurant or commercial kitchen.

Having a properly designed and maintained exhaust system helps to ensure that kitchen staff work in a safe and healthy environment, reduces the risk of fire, and provides an overall more comfortable experience for guests in the dining area.

In order to achieve this, the exhaust system must be designed to provide the proper amount of ventilation and remove heat, smoke, and other pollutants efficiently and effectively. It is essential that the system is built according to local codes and safety regulations and that it undergoes regular maintenance to keep it functioning properly.

In the next section, we’ll explore the various parts of a commercial kitchen exhaust system in more detail.

Understanding the various parts of a commercial kitchen exhaust system


One of the most critical parts of a commercial kitchen exhaust system is the hood. The hood's primary purpose is to capture the smoke, heat, steam, and grease vapors generated by the cooking process before they enter the kitchen. This process helps to keep the kitchen environment safe, clean, and comfortable for the kitchen staff.

There are different types of hoods available, including wall-mounted, island, and canopy hoods. Wall-mounted hoods are attached to the wall behind the cooking equipment and are ideal for small kitchens. Island hoods are hung from the ceiling and are suitable for larger kitchens with open space. Canopy hoods are designed for cooking equipment that generates large amounts of smoke and heat.

The hood's size should be compatible with the cooking equipment's size to ensure maximum coverage and capture efficiency. Additionally, the hood's shape and design are crucial for optimal performance. Hoods should have rounded corners, baffle filters, and built-in grease cups to minimize grease buildup and enhance safety.

It's essential to inspect the hood regularly to ensure that it's working correctly. A malfunctioning hood can pose a risk of fire and smoke inhalation, causing damage to the kitchen equipment and building. In the next section, we will discuss the importance of regular maintenance and cleaning requirements for the commercial kitchen exhaust system.


The ductwork is the component that connects the hood to the exhaust fan and the exhaust stack. Its primary function is to carry the contaminated air and smoke from the cooking area and safely discharge it outside. The ductwork can be made of various materials such as galvanized steel, stainless steel, or aluminum, depending on the specific needs of the kitchen.

It is essential to ensure that the ductwork is installed correctly and without any leaks or gaps that could allow smoke or contaminants to escape into the building. Proper installation of the ductwork also ensures that the exhaust fan can operate at its optimal capacity, thus preventing any build-up of smoke and grease within the ducts.

One important consideration for ductwork is the size. The ducts need to be properly sized to handle the amount of air being pulled out of the kitchen by the exhaust fan. Undersized ducts can lead to inadequate ventilation, while oversized ducts can lead to excessive noise and energy consumption.

Another consideration is the placement of the ductwork. The ductwork should be installed to minimize any bends, curves, or transitions, as these can restrict the airflow and increase the buildup of grease. The ducts should also be routed in a way that avoids interference with other building systems and structures.

Proper maintenance of the ductwork is crucial to ensure that it continues to function correctly and does not become a fire hazard. The ductwork should be inspected regularly for any signs of damage or blockages. Regular cleaning of the ducts, using specialized equipment and techniques, is also essential to prevent the buildup of grease and other contaminants that can lead to fire hazards and decreased air quality.

Overall, the ductwork is a critical component of the commercial kitchen exhaust system, and proper installation, sizing, and maintenance are essential for effective ventilation, energy efficiency, and safety.


The fan is an essential component of a commercial kitchen exhaust system. It works to draw out smoke, steam, and other airborne particles from the kitchen and pushes them out through the exhaust stack. Without a properly functioning fan, the kitchen will become a hot and uncomfortable working environment, with poor air quality that could compromise the health of workers.

Commercial kitchen exhaust fans are typically mounted on the roof of the building and connected to the ductwork via the exhaust hood. The fan motor should be of adequate power to pull enough air to maintain proper airflow and pressure levels throughout the system. The size of the fan will depend on the size of the kitchen, the type of cooking equipment used, and the volume of air that needs to be moved.

Fan speed can be adjusted depending on the cooking load. During peak hours when cooking activity is high, the fan will need to operate at full speed. However, during low cooking activity, the fan speed can be adjusted to save energy and reduce noise levels. Variable speed fans are designed to adjust fan speed automatically based on temperature sensors and kitchen activity levels, optimizing efficiency while ensuring good indoor air quality.

It is crucial to have a qualified technician perform regular maintenance on the fan, including cleaning, lubricating, and replacing worn or broken parts. The fan blades, housing, and motor must be cleaned regularly to remove grease and food particles that can build up over time, leading to fire hazards, unpleasant odors, and reduced efficiency.

Exhaust Stack

The exhaust stack is an important component of the commercial kitchen exhaust system. It is responsible for removing the air and pollutants from the kitchen to the outside atmosphere. The exhaust stack should be installed in a way that it creates an upward draft, drawing out the smoke and steam produced by cooking.

It is important to make sure that the exhaust stack is installed according to the local building and fire codes. Typically, the stack should be made of non-combustible materials such as stainless steel or galvanized metal. It should also be sealed tightly to prevent air from leaking in and out.

Another important consideration when installing an exhaust stack is the placement. It should be located away from areas with high pedestrian traffic and not directly over doors, windows or air conditioning intakes. The stack should be tall enough so that the exhaust gases are not dispersed near the ground level where they can affect nearby people.

It is important to remember that the exhaust stack is not just a metal tube. It should be designed to handle the volume of smoke, grease, and moisture that is generated in the kitchen. Inadequate sizing of the exhaust stack can lead to a buildup of heat and pollutants, increasing the risk of fire and affecting the efficiency of the system.

Finally, the exhaust stack should be inspected and maintained regularly to ensure that it is functioning properly. The stack can become clogged with grease, debris, and other particles that reduce its effectiveness. Regular cleaning can help prevent these issues and ensure that the system is working optimally.

In summary, the exhaust stack plays a vital role in the commercial kitchen exhaust system. Proper installation, placement, sizing, and maintenance are crucial to ensuring that it is working efficiently and effectively. Regular inspections and cleaning can help prolong the life of the system and reduce the risk of fire.

Make-up Air Unit

A make-up air unit, also known as an MUA unit, is an essential part of a commercial kitchen exhaust system. It ensures that the air being pulled out of the kitchen through the exhaust system is being replaced with fresh air from outside. Without a make-up air unit, the exhaust system could cause negative pressure in the kitchen, resulting in a decrease in efficiency, unpleasant smells, and potentially hazardous fumes.

Make-up air units can be either dedicated or combined with heating, cooling, or ventilation systems. They typically consist of a large fan, a heating element, and ductwork. The fan draws in outside air and sends it through the ductwork to the kitchen area. The heating element warms the incoming air in the winter, ensuring that the kitchen maintains a comfortable temperature even with the doors open. The make-up air unit may also be equipped with filters to remove dust and other particles from the air before it enters the kitchen.

Make-up air units are designed to work in tandem with the exhaust system. When the exhaust fan turns on, the make-up air unit fan speeds up to ensure that the proper air balance is maintained. This helps to prevent negative pressure and ensures that fumes and smoke are efficiently exhausted from the kitchen.

It is important to have your make-up air unit regularly inspected and maintained to ensure it is functioning correctly. A malfunctioning make-up air unit can result in a drop in efficiency, an increase in energy costs, and potential safety hazards. By ensuring your make-up air unit is working properly, you are protecting the safety of your employees and patrons and ensuring the longevity of your commercial kitchen exhaust system.

Fire Suppression System

A fire suppression system is a crucial component of any commercial kitchen exhaust system. These systems are designed to quickly and effectively suppress fires that may start within the kitchen. Many local fire codes require that commercial kitchens have a fire suppression system installed.

Fire suppression systems typically use a combination of chemicals, such as wet chemicals or dry powders, and automatic detection devices to quickly detect and suppress a fire. In addition to detecting and suppressing fires, these systems also work to minimize the spread of fire and protect individuals within the building.

There are two main types of fire suppression systems: pre-engineered systems and engineered systems. Pre-engineered systems are typically used in smaller kitchens and are pre-designed for easy installation. Engineered systems, on the other hand, are customized to fit the specific needs of a larger kitchen and are designed by a professional engineer.

Regardless of the type of fire suppression system you choose, it’s important to make sure that it is properly installed and maintained. Regular inspections and maintenance will ensure that the system is functioning properly and can effectively suppress a fire if needed.

Overall, a fire suppression system is a critical component of any commercial kitchen exhaust system. It’s important to work with a qualified professional to ensure that the system you choose meets all local codes and is properly installed and maintained. With the right system in place, you can feel confident that your kitchen is safe and protected.

Maintenance and Cleaning Requirements

One of the most important aspects of owning and operating a commercial kitchen exhaust system is understanding the necessary maintenance and cleaning requirements. Neglecting to properly maintain and clean your exhaust system can lead to a variety of issues, including poor air quality, health hazards, fire hazards, and even damage to the system itself.

To ensure that your commercial kitchen exhaust system is functioning properly and safely, it's important to schedule regular maintenance and cleaning services with a qualified professional. These services may include cleaning the hood, ductwork, fan, and exhaust stack, as well as inspecting and repairing any damaged or worn components.

The frequency of these services will depend on several factors, including the volume of cooking that takes place in your kitchen, the type of food that is prepared, and the age and condition of your exhaust system. Your local health department may also have specific guidelines regarding the frequency of maintenance and cleaning.

In addition to scheduling professional services, it's important to establish and maintain a regular cleaning and maintenance schedule within your kitchen. This may include wiping down the hood and other components daily, inspecting and replacing filters regularly, and ensuring that all components are functioning properly.

Finally, it's important to prioritize the use of high-quality and effective cleaning products and equipment. Using improper or ineffective products can lead to a buildup of grease and other contaminants, which can then lead to health and fire hazards.

Overall, proper maintenance and cleaning of your commercial kitchen exhaust system are essential for ensuring safe and healthy kitchen operations. Be sure to work with a qualified professional and establish a regular cleaning schedule to keep your system in top condition.

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