Cassette air filters – pre-filters for ventilation and air conditioning systems

Cassette filters – reliable pre-filtration for HVAC systems

Cassette filters are widely used air pre-filters designed for the first stage of filtration in ventilation and air conditioning systems. They play a crucial role in protecting downstream components such as fans, heat exchangers and higher-efficiency filters by removing coarse and medium airborne contaminants.

These filters are commonly applied in HVAC installations with standard to moderate air cleanliness requirements, where stable airflow, low pressure drop and reliable operation are essential.

Filtration concept and performance

Cassette filters are primarily used for initial air purification. Depending on system requirements, they can function as:

• Pre-filters, extending the service life of higher-efficiency filters

• Main filters in simpler ventilation systems, depending on the selected filtration class

Thanks to their high dust holding capacity combined with low airflow resistance, cassette filters support efficient and economical system operation.

Available filtration classes include G3, G4, M5 and F7, making them suitable for a wide range of HVAC applications.

Filter media and materials

The filtration media used in cassette filters is based on high-quality synthetic polyester fibers with a progressive fiber structure. This design provides an optimal balance between:

• Filtration efficiency

• Dust holding capacity

• Low pressure drop

• Stable airflow throughout filter lifetime

In selected variants, glass fiber filter media is applied where additional rigidity or specific performance characteristics are required.

Construction variants

Cassette filters are available in multiple constructions to match different installation and performance requirements.

Cassette filters with pleated filter media

These filters use a pleated (folded) filter medium, increasing the effective filtration surface and improving dust holding capacity.

• Frame made of galvanized steel sheet for corrosion resistance

• Filter media machine-molded and thermoset at high temperature

• High-quality adhesive ensures secure bonding, even at high airflow rates

• Reinforcement beams applied for larger dimensions to ensure structural stability

Cassette filters with flat filter media

Flat cassette filters are designed for applications requiring a simple, robust construction.

• Frame made of galvanized steel sheet

• Filter media positioned between two galvanized metal grids

• Grids stabilize the filter media and maintain correct airflow

• Entire assembly secured with breakable rivets

Typical applications

Cassette filters are used in a wide variety of ventilation and air conditioning systems, including:

• Hotels

• Office buildings

• Shopping centres

• Public buildings

• Control rooms and control cabinets

• Server rooms and technical spaces

• Heat pump installations

• Industrial facilities with standard air cleanliness requirements

They are suitable for heating, cooling and ventilation installations across commercial and industrial environments.

System integration

Cassette filters are typically installed as pre-filters, protecting higher-efficiency filtration stages such as compact or HEPA filters. In simpler HVAC systems, they may also serve as the primary filtration element.

<p> In multi-stage HVAC systems, cassette filters are commonly used upstream of <a href="/collections/compact-filters">compact filters</a> or <a href="/collections/hepa-filters">HEPA filters</a> to extend service life and maintain system efficiency. </p>

Custom dimensions – manufactured to order

Cassette filters supplied by Filtra International are manufactured to order and can be delivered in custom dimensions.

• Custom length × width × height (mm)

• Suitable for retrofit and new installations

• Compatible with standard and bespoke HVAC housings

This flexibility ensures reliable integration into virtually any ventilation system.

Manufacturing origin & quality

Cassette filters supplied by Filtra International are manufactured in Europe, ensuring:

• Consistent production quality

• Compliance with European manufacturing standards

• Reliable supply and short lead times

Product configuration & quotation

Cassette filters are supplied on a quotation basis, allowing configuration of:

• Filter construction (flat or pleated)

• Filter media type

• Filtration class (G3, G4, M5, F7)

• Frame material

• Exact dimensions and quantity