Hood Filter Buying Guide

If you have questions about commercial hood filters – you’re in the right place. Here you’ll find helpful information, tools, and answers to all the frequently asked questions about hood filter purchasing, maintenance, and fire code compliance.

Hood Filter Sizing

The most common questions we receive are “how do I measure my hood filters” and “how many hood filters do I need”. We’re going to answer both questions and give you some tools to make this very easy.

How To Measure Hood Filters?

Industry standard sizes are ordered with the vertical (top to bottom) dimension first and the horizontal (left to right) dimension second.

Before ordering hood filters, be sure to round up to the nearest 1/2" – then select the corresponding size.

For example, if the actual filter size is 9 1/2" x 15 1/2", you would order a 10" x 16" hood filter. Below are two measurement examples and a conversion chart showing standard trade size filters and their actual dimensions.


DOWNLOAD: Hood Filter Measuring Guide PDF

VIDEO: How to Measure Hood Filters and Choose the Right Size


Hood Filter Sizing Calculator

This easy-to-use calculator will help you determine the size and quantity of filters needed to fill your hood system opening. Just 3 easy steps...

1. Select Filter Type:

2. Enter the Horizontal Width of Your Hood Opening: inches.Measure from the INSIDE far left (where the filters appear to slide in) to the INSIDE far right.

3. Choose the Vertical Height of Your Hood Opening: Measure from the INSIDE bottom (where the filters appear to slide in) to the INSIDE top.

Here's What You Need...

_ - _ x 16 filters

_ - _ x 20 filters

_ - _ x 25 filters

Horizontal Width of Hood Opening: _"

Total Horizontal Width of Hood Filters: _"

Leftover Space: _"

If you have more than 1.5" of leftover space, you can purchase hood filter spacers to cover the area. Filter spacers are available in custom widths up to 6" wide.

Browse All Filters

IMPORTANT: Horizontal measurement should just be the area that needs to be filled by the hood filters. Keep in mind that you’ll need extra space to get filters in and out of the hood.

Please double check your measurements to avoid returns and additional costs. HoodFilters.com is not responsible for ordering errors or improper measurements.

How to Choose the Right Type of Hood Filter

Selecting the right filter for your hood system is an important decision. It can also be a daunting one with all the different kinds to choose from. Here are some valuable resources that will eliminate the guesswork and get you on track…

VIDEO: How to Choose the Right Type of Hood Filter

VIDEO: What is a Spark Arrestor Filter

DOWNLOAD: Types of Hood Filters

Filter Hooks for Captive-Aire Hoods

Hooks are available for all Heavy Duty Stainless Steel, Aluminum, and Galvanized hood filters to fit Captive-Aire style hood systems.  



DOWNLOAD: Hood Filter Hooks for Captive-Aire Hood Systems

Hood Filter Spacers vs. Custom Hood Filters

If standard size hood filters don’t perfectly fit the width of your hood system, you can still avoid the high cost of custom made filters by using filter spacers.

A hood filter spacer is a solid piece of curved metal that fills any open space left after installing your hood filters. You can order spacers in variety of sizes with a maximum width of 6”. Spacers are available in aluminum, galvanized, or stainless steel.

VIDEO: How to Use Hood Filter Spacers vs. Custom Filters

VIDEO: How to Measure Hood Filter Spacers

How to Clean Your Hood Filters

Hood filters should be cleaned daily or on regular cleaning schedule to keep them free of grease and able to provide maximum filtering capabilities.

If hood filters are neglected, they can’t do their job – which is to provide a flame barrier in the event of a cooking fire below and to catch grease laden vapors before they reach the duct system. 

When hood filters are clogged from infrequent cleaning, it causes many problems including extreme fire hazards, higher utility costs, and strain on the exhaust system that hampers the ability to pull heat and smoke from the kitchen.

Cleaning Options:

Hand Wash: The best way to clean hood filters is good old-fashioned hand washing.  Use hot soapy water and dry them immediately after cleaning.  Power washing is also acceptable.

Dishwasher: You can also run filters through a high temp dishwasher with soap and water.  WARNING: do not use bleach, as it will quickly corrode the hood filters.  In fact, stay away from any kind of chemical unless it’s non-corrosive and designed for filter cleaning.

Soak Tank: Investing in a soak tank is another option that cuts out the time and labor involved with manual cleaning.  Simply fill up the tank with water, then add non-corrosive and metal-safe cleaner, and let the filters soak overnight.  The next day, take the filters out, rinse, and they are ready to use.

DOWNLOAD: How to Clean Hood Filters PDF

How to Install Hood Filters

Hood filters should always be installed with the baffles running in a vertical position.  This allows the grease to be drawn down and into the collection system by gravity.  For safer and easier install see the Baffle Boss hood filter removal tool.

VIDEO: Baffle Boss Hood Filter Lifting Tool Demo

When to Replace Hood Filters

Just like you should clean hood filters on a daily basis, you should also inspect them at the same time and look for dents, holes, corrosion, or disfigurement of any kind.  If a filter is damaged or worn, it’s important to replace it right away.

Continuing to use damaged hood filters will lead to grease build up in hood duct, which poses a dangerous fire and safety hazard.

NFPA 96 Fire Codes for Hood Grease Filters

NFPA 96 is a set of codes and standards for ventilation control and fire protection of commercial cooking operations by the National Fire Protection Association. These are the standards that fire marshals follow and commercial cooking operations are required to adhere to.

The following NFPA 96 excerpts are related to hood grease filters in commercial kitchen exhaust hoods.

 6.1 Grease Removal Devices

6.1.1 – Listed grease filters, listed baffles, or other listed grease removal devices for use with commercial cooking equipment shall be provided

6.1.2 – Listed grease filters and grease removal devices that are removable but not an integral component of a specific listed exhaust hood shall be listed in accordance with UL 1046

6.1.3 – Mesh filters shall not be used unless evaluated as an integral part of a listed exhaust hood or listed in conjunction with a primary filter in accordance with UL 1046 – Grease filters shall be listed and constructed of steel or listed equivalent material. – Grease filters shall be of rigid construction that will not distort or crush under normal operation, handling, and cleaning conditions – Grease filters shall be arranged so that all exhaust air passes through the grease filters. – Grease filters shall be easily accessible and removable for cleaning. – Grease filters shall be installed at an angle not less than 45 degrees from the horizontal


NFPA 96 Fire Codes for Spark Arrestor Filters (Solid Fuel Cooking Systems)

14.5.1 – Grease removal devices shall be constructed of steel or stainless steel or be approved for solid fuel cooking

14.5.2 – If airborne sparks and embers can be generated by the solid fuel cooking operation, spark arrestor devices shall be used prior to using the grease removal device to minimize the entrance of the sparks and embers into the grease removal device and into the hood and duct system.

14.5.3 – Filters shall be a minimum of 1.2 m (4 ft) above the appliance cooking surface