Pocket Bag Filters

Office Buildings • Hospitals • Hotels • Industrial Buildings

Pocket Bag Filters

Call For Pricing and Delivery 905-403-0160

Pocket Bag Air Filters are typically used as a secondary or final filter used after (behind) a pleated filter. Bag air filters, often referred to as bag filters and pocket filters, come in three levels of efficiencies; 65, 85 and 95% - or MERV 11, 13 and 15 ratings.

The filter is made with pieces of media, sealed together to form pockets. Each bag air filter can have a specified number of pockets, whether they be 3 pocket bag filter, or 6 pocket bag filter, the pockets themselves can vary in length. With these combinations of pockets and lengths, many surface areas sizes can be created. Generally, a larger surface area will give you better Dust Holding Capacity (DHC) and longer service life of the filter.

A typical 24x24x2 bag air filter high capacity pleat has about 18 square feet of media within its cardboard frame. A standard size pocket filter, such as 24x24x22 deep - 6 pockets will have approximately 45 square feet of media. With a larger 24x24x36 deep - 8 multi pocket bag filter, the surface area increases to over 100 square feet of filter media.

When using pocket air filters with a pleat, common practice is to have a lower efficient pleat paired with a higher efficiency bag filter. Most commercial building operators use a MERV 8 pre-filter. This more economical pleated filter will help capture the larger particles in the air and extend the service life of the bag filters downstream.

Normally, a pleated filter may be changed 3 to 4 times a year, while a 24x24 bag filter might last up to a year with proper maintenance of the pre-filters.

What are the ideal applications for a bag filter?

Pocket Bag filters are designed for constant flow or air volume, through the pockets of the filter. The moving air “inflates” the pockets, creating a larger surface area. If the air volume slows dramatically, or stops altogether, the pockets tend to deflate, and collapse upon each other. This can cause off loading and permanently damage the bags.

Therefore, bag air filters are not recommended in Variable Air Volume (VAV) applications where the air system shuts down over a certain period (i.e. weekends). Bag filters are ideal in applications where the air systems work around the clock, like a larger office tower where it isn’t feasible to shut/slow down air volumes over a period of time. A computer data centre, or a museum are also examples which typically require constant air flows, 24/7.

Bag HVAC filters are also used in older applications, where VAV fans have not been installed.

In applications where the air speeds are adjusted daily, or hourly, it is recommended to use a box style filter. Box filters are designed to operate under VAV conditions, the construction of the box allows the pleated filter media to remain in place, with or without air volumes supporting the filter.

Once you decide which secondary filter you need, bag or box style, you will need to choose an efficiency. Our bag filters are offered in MERV 11, 13 and 15 to accommodate almost every application you may need.

Please contact United Filter, and we will gladly help you decide what is best for you and your application(s).

We supply medium to high efficiency pocket filters for both commercial and industrial requirements. This includes oil mist and fume collections, as well as heavy concentrated airborne contaminants.

Each bag filter is thoroughly inspected. This product’s performance has been tested by independent laboratories according to ASHRAE 52.1 - 1992 norms. Results showed low initial resistance and a longer life.


Performance Details:

• enhanced dust retention capacity
• longer lasting
• better air quality
• available in 3 efficiencies
• interchangeable design
• UL class 2



GREEN 65% - MERV 11

Designed to provide high efficiency filtration, this synthetic microfiber filter is suitable for areas where cleaner air is required.




PINK 85% - MERV 13

Low overall resistance and high efficiency make this filter a popular choice for most applications.



YELLOW 95% - MERV 15

This ultra-high efficiency synthetic microfiber filter collects minute particles in environments where clean air is crucial such as in hospitals and laboratories.


Call Today for Pricing and Delivery 905-403-0160



  • 24 gauge galvanized steel frame
  • internal support for each bag
  • area around bags is ultrasonic sealed to ensure consistent air flow
  • used in side or front access housing for 2nd stage filtration
  • standard and custom sizes


Call us at (905) 403-0160, or complete the quick form below and we will get back to you within one business day.