With so many different features and options, not to mention technical details such as airflow and static pressure, you may be asking yourself “Which commercial kitchen exhaust fan is right for me?” To help you decide, we will take a look at the basics of selecting an exhaust fan for your specific needs.

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All fans perform the same essential task – moving air from one place to another. Commercial kitchen exhaust fans are an essential part of your kitchen ventilation system. We depend on them to remove dust, dirt, grease-laden air, and smoke from our kitchens.

There are five main aspects to consider when choosing a commercial kitchen exhaust fan: model, static pressure, air volume flow rate, motor horsepower, and loudness. Understanding how these relate to your needs will help assist you in choosing the exhaust fan that is right for you.

1) Commercial Kitchen Exhaust Fan Model

Where will you install your exhaust fan?

One of the first things to consider when selecting an exhaust fan model is the location you plan to install the fan. Most commercial kitchen exhaust fans are designed to be mounted in one of three locations: rooftop, wall mount, or in the duct. Where your fan is mounted will affect the housing of the fan and any accessories you may want to purchase along with it. For example, a rooftop exhaust fan typically requires a roof curb for proper installation.

Should you get a belt drive fan or a direct drive fan?

The next thing you’ll need to decide is whether you want a direct drive or a belt drive commercial kitchen exhaust fan. Part of this decision may be based on how many CFM you’ll need (more on that later).

Belt drive fans are driven by a belt and motor pulley system that is connected to the shaft of the motor. Direct drive fans have fan wheels or blades that are attached directly to the shaft of the motor.

Direct drive commercial kitchen exhaust fans are commonly considered more efficient than a belt drive fan. As much as 10% efficiency loss due to belt drag and belt vibration has been shown in some studies. Direct drive fans also tend to require less maintenance and repair as they have fewer moving parts and components.

Unfortunately, this loss of efficiency can be made even worse if the fan is not properly installed and maintained. Belts may need to be tightened, adjusted, and eventually replaced. Sheaves and additional bearings in belt drive fans may increase points of mechanical failure. Shafts, pulleys, and pillow blocks must be correctly aligned.

But belt drive fans do have their advantages and are consistently and successfully employed in many commercial kitchen ventilation systems. Belt drive exhaust fans are less expensive, have higher speed motors, and allow more precise control of the fan speed. Speeds can also easily be adjusted in the field using pulley changes.

For high temperature applications, belt drive fans have the advantage of having the motor outside of the airstream. It really comes down to your budget and the specific needs of your ventilation system.

Direct drive fans, on the other hand, have a higher up front cost but will likely have fewer maintenance issues and lower upkeep costs for fan accessories such as supports, pulleys, and bearings. Whereas a typical belt drive fan has five potential points of failure (including belts, motor, shaft and pillow block bearing), a direct drive fan has only one – the motor.

On a direct drive commercial kitchen exhaust fan, the motor is mounted directly to the rotor shaft or fan axle. The power is transmitted directly to the blades, spinning them at the same speed as the motor’s rotation. This makes a direct drive fan more efficient. Additional advantages include fewer vibrations, lighter weight, and a more compact installation.

So which one is right for you? If you need a low volume fan of 2,000 CFM or less with low static pressure of 0.50” or less, a direct drive commercial kitchen exhaust fan is a very economical choice. However, if your exhaust fan needs are above 2,000 CFM or you require static pressures above 0.50”, the flexibility you get from a belt drive fan will be an important consideration. And most exhaust fans for applications above 122°F are nearly always belt drive fans.

2) Commercial Kitchen Exhaust Fan Static Pressure

What is static pressure?

Simply put, static pressure is the resistance against air as it travels through your ventilation system. It relates to the status of equilibrium when the air supplied and the air exhausted are equal. Also referred to as system air resistance or friction loss, the static pressure in a system relies on all parts working properly. Exhaust fans, ducts, filters – if one element is deficient, the entire system gets thrown off.

Static pressure is measured by a manometer, which originally used a column of water to show the amount of static pressure. As air pressure increased, the column of water in the manometer would rise. That is why static pressure is still measured in inches of water. For ventilation applications, it is expressed in inches per 100 feet of duct. One pound per square inch is equivalent to 27.7” sp and static pressure in exhaust fan systems is usually less than 2” sp, or 0.072 psi.

The main ventilation system components directly affecting static pressure are duct surface material, the length of the duct, duct system design, and the volume of air being pushed through. Getting an accurate static pressure measurement is critical to selecting the proper exhaust fan. When your duct work and exhaust system are calculated properly, your system will run as it should.

But if the CFM of your commercial kitchen exhaust fan is too low, you will likely have poor circulation and air distribution. And if the CFM of your fan is too high, your system will create to much static pressure which will cause air loss and wastes energy. If the air in your system is encountering a lot of resistance, the static pressure increases. And with higher static pressure, you’ll encounter air loss and higher energy costs.

3) Commercial Kitchen Exhaust Fan Air Volume Flow Rate

Air velocity is measured in linear feet per minute, or LFM. It is measured as air passes through a duct. Then, the LFM is multiplied by the volume of the duct in cubic feet to get a cubic feet per minute (CFM) measurement of air movement – also known as the air flow volume rate.

Typically, the hood you purchase will dictate what CFM your exhaust fan will need to be. Factors affecting your hood choice include what type of cooking equipment you will use and the volume of cooking in your kitchen. For example, a large are of open flame wok cooking will require significantly more exhaust than the usual griddle or gas range.

The National Fire Protection Association (NFPA) 96 Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations says that the air velocity through any duct shall not be less than 152.4 m/min (500 ft/min) and exhaust air volumes for hoods shall be of a sufficient level to provide for capture and removal of grease-laden cooking vapors. Lower exhaust air volumes are permitted during no-load cooking conditions as long as they are sufficient to capture and remove flue gases and residual vapors from cooking equipment.

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Here are some common guidelines for determining the minimum CFM of your commercial kitchen exhaust fan:

4) Commercial Kitchen Exhaust Fan Motor Horsepower

Horsepower measures the power or energy that is output by the motor of your exhaust fan. One horsepower is equivalent to 746 watts in the International System of Units. The amount of power that a motor uses is not purely what it is capable of, but depends more on the manner in which it is loaded.

Similar to a car’s engine, it is not the amount of power that the motor can deliver, but instead how much power is required to do the work – or in the case of an exhaust fan, how much power is needed from the motor to spin the fan blades at a specific speed.

And as we mentioned earlier when we discussed direct drive vs. belt drive exhaust fans, motor power usage is also closely related to the motor’s efficiency. When it comes down to it, the horsepower of an exhaust fan motor relates directly to how much air can be moved with each watt of power output by the fan.

In other words, exhaust fans with a higher CFM need more energy efficiency. Start by looking at how much air is moved by the exhaust fan at the maximum expected operating static pressure and the fan’s energy efficiency rating. Finding the right combination of CFM and horsepower for your exhaust fan will help make sure your ventilation system operates efficiently and with fewer maintenance issues.

5) Commercial Kitchen Exhaust Fan Loudness

Depending on the location of your exhaust fan, the sound generated by it may be a consideration. If exhaust fan noise is a concern for you, be sure to check the sone rating on the fan before purchasing. In general, the higher the CFM, the higher the sone rating.

Fan loudness is generally expressed in sones. Sones are an internationally recognized linear measurement equivalent to 40 phons. As an example, an average refrigerator has a loudness of about 1 to 2 sones and a typical residential bathroom exhaust fan is about 2 to 5 sones. Suggested levels of sones for a commercial kitchen are between 7 and 21 sones (56-72 dBA).

Putting It All Together

As you can see, selecting the right equipment for your commercial kitchen ventilation system is extremely important. A properly designed and maintained system will provide years of service and significantly improve the environment in your kitchen and restaurant.

Watch this video to learn more about the upblast exhaust fans and accessories available at HoodFilters.com.

What Products Should Be Under the Hood in a Commercial Kitchen?

Commercial kitchen equipment that does not require a hood

Ventilation systems (also known as hoods) are required in a commercial kitchen setting. They provide fire protection for the kitchen and create a comfortable working atmosphere for your staff and a pleasant experience for your residents by removing odors, heat, steam, grease and smoke. Know the difference between hood types so you can identify and select the right products to go under them as well as commercial kitchen equipment that does not require a hood.

Know your hood types: type 1 hood vs type 2

There are a few key differences between commercial kitchen hood type 1 vs type 2:

• Type I hoods are required for equipment that produce smoke or grease-laden fumes. This includes equipment such as fryers, ranges, griddles, convection ovens, tilt skillets and broilers. 
• Type II hoods are used where grease isn’t present to remove steam, vapor and odors. These types of hoods are generally used for dishwashers, steam tables and steamers.

Type 2 hood example:

Equipex Countertop Hood – perfect for cooking in a converted space with type II electrical appliances, such as panini grills or induction.

With this particular type 2 kitchen hood, you can add a pre-piped Ansul system as an accessory, which would make them good for type 1 as well as type 2.

Maximize budget dollars through space efficiency: Type 1 hood cost vs Type 2

Type 1 (exhaust hood) cost:

A hood in a commercial kitchen is high-end real estate. Currently, we are seeing prices at around $16,000 for 2 – 10′ type 1 hoods.  Meaning, it can cost anywhere from $900 to $1,700 per linear foot, depending on what state you live in. Because of the high cost, it’s important to use that space as efficiently as possible. 

Type 2 (condensate hood) cost

Since you can use Type 2 kitchen hoods without ductwork you can oftentimes find these hoods at a generally cheaper price. In , we’re seeing prices land around $1,800.

Not all electrical equipment needs to be under a hood

In the past, the general rule for commercial kitchens was that if a product created heat or steam, it needed to go under a hood. While that still holds true for all gas equipment, there are a few exceptions for electrical equipment. Some examples of electric equipment and commercial ovens that may not need to go under a hood include:

• Certain types of boilerless steamers
• Countertop steamers
• Accelerated cooking ovens
• Certain models of combi ovens
• Cook and hold units
• Multi-cook ovens

It’s important to remember that even if a product is rated ventless, your local inspector still has the final word. So be sure to connect with them to find out how they interpret the code prior to making a purchase.

Find new, innovative equipment solutions that don’t require a hood!

Hobart Ventless Door-Style Dishmachine – redirects the heat and steam back into the unit to warm the incoming cold water, providing both water and energy savings.

Merrychef eikon e2s High-Speed Oven – ventless cooking capabilities through built-in catalytic converter.

Combi Electric Heated Boilerless oven – electric tabletop models offer ventless versatility. Operators can choose between manual and automated cooking platforms for ease of use.

Commercial Oven Ventilation Accessories

If you find yourself struggling to fit everything under the primary hood in your kitchen, then you might want to shop for ovens that have a hood as an accessory for you to cook in a converted space. There are two that we’d suggest:

The Bakerlux Convection Ovens – this brand offers both full size and half size convection ovens with a ventless hood capture system as an optional accessory for purchase. The VariKwik Oven – the VariKwik Oven is available in large and standard sizes with charcoal and stainless steel color options. These ovens also have a 120v and a 220 v ventless hood accessories as well.

Whether your community is looking for traditional equipment or something new and innovative, Direct Supply has a variety of products to meet your needs at DirectSupply.net.

Contact us to discuss your requirements of mccb supplier. Our experienced sales team can help you identify the options that best suit your needs.