Pleated Air Filters for HVAC, AHU, FCU and Industrial Applications

Pleated Air Filters are air filters manufactured with filter media folded into a series of pleats to increase the effective filtration area within a compact frame. Compared with flat media filters of similar face dimensions, the pleated structure can provide a larger media area, improved dust-holding capacity and longer service life when properly designed and operated.

Pleated filters are widely used in HVAC systems, Air Handling Units (AHUs), Fan Coil Units (FCUs), Fresh Air Units, ventilation systems, commercial buildings, factories, hospitals, data centers and cleanroom pre-filtration systems.

VIETPHAT supplies Pleated Air Filters in a wide range of dimensions, depths, filtration efficiencies, frame materials and media constructions to support commercial, industrial and cleanroom air filtration requirements.

What Are Pleated Air Filters?

A Pleated Air Filter uses filter media that has been folded into repeated pleats rather than installed as a flat sheet.

The pleated configuration increases the amount of filtration media that can be installed within a given filter face area.

This design can provide several advantages:

• Higher effective media area.
• Improved dust-holding capacity.
• Longer service life.
• More compact construction.
• Potentially lower average pressure drop for a given filtration requirement.
• Improved mechanical stability when properly supported.

How Do Pleated Air Filters Work?

As air passes through the pleated media, airborne particles are captured within or on the surface of the filter fibers.

The effectiveness of the filter depends on several factors including:

• Filter media type.
• Filtration efficiency.
• Pleat depth.
• Pleat spacing.
• Face velocity.
• Rated airflow.
• Dust loading.
• Filter construction.

The purpose of pleating is not simply to make the filter look more compact. It is primarily used to increase the available media area while maintaining manageable airflow resistance.

Main Benefits of Pleated Air Filters

• Large filtration surface area.
• Good dust-holding capacity.
• Compact installation depth.
• Suitable for many HVAC applications.
• Available in multiple filtration classes.
• Can be used as pre-, primary or intermediate filters.
• Helps protect downstream filters.
• Can help extend HEPA filter service life.

Common Types of Pleated Air Filters

1. Pleated Pre Filters

Pleated Pre Filters are designed for primary or coarse filtration and are commonly installed at the first stage of HVAC and AHU systems.

Their primary role is to capture coarse airborne dust before it reaches downstream components or higher-efficiency filters.

2. Pleated Panel Filters

Pleated Panel Filters combine a panel-style frame with pleated filter media.

This is one of the most common configurations used in commercial and industrial HVAC systems.

3. Medium Efficiency Pleated Filters

Medium Efficiency Pleated Filters provide greater particle-removal performance than coarse pre-filters and may be used as an intermediate filtration stage.

Typical applications include:

• Commercial AHUs.
• Industrial HVAC systems.
• Factories.
• Hospitals.
• Cleanroom pre-filtration.

4. Fine Pleated Filters

Fine Pleated Filters use higher-efficiency media for better control of smaller airborne particles.

They may be installed as final filters in general ventilation systems or as pre-filters before HEPA filters.

5. Mini-Pleat Filters

Mini-Pleat Filters use very closely spaced pleats separated by hot-melt beads or other spacing technology.

This construction allows a very large amount of media to be installed in a compact filter package.

Mini-pleat technology is commonly used in:

• Compact Filters.
• V-Bank Filters.
• HEPA Filters.
• ULPA Filters.
• FFU Filters.

Pleated Air Filter Types by Application

Filter Type	Typical Function	Common Application
Pleated Pre Filter	Coarse particle removal	AHU, FCU, fresh air systems
Pleated Panel Filter	Primary or intermediate filtration	Commercial HVAC
Medium Pleated Filter	Intermediate particle filtration	Industrial AHUs
Fine Pleated Filter	Higher-efficiency particle filtration	Hospitals, cleanroom pre-filtration
Mini-Pleat Filter	High media area in compact construction	Compact, V-Bank and HEPA filters

Pleated Air Filters for HVAC Systems

Pleated Air Filters are widely used in HVAC systems because they provide a practical balance between filtration performance, installation depth, dust-holding capacity and pressure drop.

A typical HVAC filtration system may include:

• Stage 1: Pleated Pre Filter.
• Stage 2: Bag Filter or Fine Filter.
• Stage 3: HEPA Filter when required.

The correct filtration arrangement depends on the required indoor air quality, fan capability, system pressure and application.

Pleated Air Filters for AHUs

Air Handling Units are one of the most common locations for Pleated Air Filters.

The filter may be installed:

• At the air intake.
• Before cooling coils.
• Before intermediate filtration stages.
• Before final HEPA filters.

Important parameters include:

• Filter dimensions.
• Rated airflow.
• Filtration class.
• Initial pressure drop.
• Final pressure drop.
• Dust-holding capacity.
• Filter depth.
• Pleat design.

Pleated Air Filters for FCUs

Fan Coil Units generally require shallow filters with low resistance because the fan has limited available static pressure.

Pleated filters can be used in FCUs if they are designed with appropriate depth and pressure-drop characteristics.

Pleated Air Filters for Fresh Air Units

Fresh Air Units draw outdoor air into buildings, making the first filtration stage particularly important.

Pleated Pre Filters can help capture outdoor dust before the air passes through coils and higher-efficiency downstream filters.

Pleated Air Filters for Commercial Buildings

Commercial facilities commonly use Pleated Air Filters in AHUs and ventilation equipment.

Applications include:

• Office buildings.
• Hotels.
• Shopping centers.
• Retail stores.
• Schools.
• Public buildings.

Pleated Air Filters for Industrial Facilities

Industrial facilities often require reliable primary and intermediate filtration because dust loading can be higher than in typical commercial buildings.

Pleated Air Filters may be used in:

• Electronics factories.
• Semiconductor facilities.
• Food processing plants.
• Pharmaceutical manufacturing.
• Automotive factories.
• Medical device manufacturing.
• General industrial facilities.
• Warehouses and logistics centers.

Pleated Air Filters for Cleanrooms

Pleated filters are commonly used as upstream pre-filtration in cleanroom HVAC systems.

A typical cleanroom filtration sequence may include:

• Pleated Pre Filter.
• Medium or Fine Filter.
• HEPA Filter.
• ULPA Filter when required.

Effective upstream filtration can reduce dust loading on high-cost HEPA and ULPA filters.

Pleated Air Filters for Hospitals

Hospitals often use multiple filtration stages. Pleated filters may be used as primary or intermediate filters before fine or HEPA filtration.

The actual filter selection should follow the HVAC design and requirements of the specific healthcare area.

Pleated Air Filters for Data Centers

Data centers require continuous cooling and are sensitive to dust accumulation.

Pleated Air Filters can help control particulate contamination, but pressure drop should be carefully evaluated because fan energy consumption is an important operating-cost factor.

Pleated Air Filters and ISO 16890

ISO 16890 is widely used to classify general ventilation filters according to their tested efficiency against particulate matter.

Pleated Air Filters can be designed for various ISO 16890 groups including:

• ISO Coarse.
• ePM10.
• ePM2.5.
• ePM1.

The actual classification depends on tested filter performance, not simply on the pleated construction.

Pleated Air Filters and Former EN 779 Classes

Older specifications may still reference former EN 779 classes such as:

• G3.
• G4.
• M5.
• M6.
• F7.
• F8.
• F9.

These classifications are still widely recognized in the market, but new specifications should use ISO 16890 performance data when available.

G4 Pleated Air Filters

G4 Pleated Air Filters are a common market term for coarse pleated filters classified under the former EN 779 system.

They are commonly used as pre-filters in:

• AHUs.
• FCUs.
• Fresh Air Units.
• Commercial buildings.
• Factories.
• Cleanroom HVAC systems.

M5 Pleated Air Filters

M5 Pleated Filters represent a higher filtration level than traditional G4 coarse filters under the former EN 779 classification.

They may be used as intermediate filters in general HVAC and industrial ventilation systems.

F7 Pleated Air Filters

F7 Pleated Filters were classified as fine filters under the former EN 779 standard and may be used in applications requiring higher particle removal performance.

For new projects, actual ISO 16890 performance should be reviewed instead of relying only on the former F7 designation.

Pleated Air Filters vs Flat Panel Filters

Criteria	Pleated Air Filter	Flat Panel Filter
Media Configuration	Folded into pleats	Relatively flat media
Media Area	Higher	Lower
Dust-Holding Capacity	Generally higher	Generally lower
Filter Depth	Varies by design	Usually shallow
Typical Application	Primary to fine filtration	Mainly coarse pre-filtration

Pleated Air Filters vs Bag Filters

Criteria	Pleated Air Filter	Bag Filter
Construction	Rigid pleated media	Flexible filter pockets
Installation Depth	Usually compact	Often deeper
Media Area	High	Very high depending on pocket length
Application	Primary/intermediate filtration	Intermediate/fine filtration

Pleated Air Filters vs HEPA Filters

Pleated Air Filters should not automatically be considered HEPA filters.

Pleated describes the physical arrangement of the media, while HEPA describes a high-efficiency performance classification.

Many HEPA filters use mini-pleated media, but ordinary pleated HVAC filters generally have much lower filtration efficiency than HEPA filters.

Pleated Air Filters vs Pre Filters

Pleated Air Filter describes a filter construction, while Pre Filter describes the filter's role in the system.

A pleated filter may be used as a pre-filter, medium filter or fine filter depending on the media efficiency.

Why Pleat Design Matters

The performance of a pleated filter depends not only on the amount of media but also on how the pleats are designed.

Important factors include:

• Pleat depth.
• Pleat spacing.
• Pleat stability.
• Media stiffness.
• Air distribution.
• Face velocity.

If pleats are packed too tightly, airflow distribution can become uneven and the expected benefit of additional media area may be reduced.

Pressure Drop of Pleated Air Filters

Pressure Drop is one of the most important factors when selecting a Pleated Air Filter.

The pleated design allows more media area to be used, which can help keep media velocity relatively low. However, actual resistance still depends on media efficiency, pleat geometry and airflow.

As dust accumulates, pressure drop increases and may cause:

• Reduced airflow.
• Higher fan load.
• Higher energy consumption.
• Reduced HVAC performance.

Dust-Holding Capacity of Pleated Air Filters

The increased media area of a pleated filter can provide greater dust-holding capacity than a comparable flat filter, depending on the filter design.

Higher dust-holding capacity can help:

• Extend filter service life.
• Reduce maintenance frequency.
• Reduce replacement labor.
• Protect downstream filters.

Important Pleated Air Filter Specifications

Parameter	Description
Dimensions	Width × Height × Depth
Filter Efficiency	According to ISO 16890 or applicable standard
Rated Airflow	Design air volume through the filter
Initial Pressure Drop	Resistance when the filter is new
Final Pressure Drop	Recommended service or replacement limit
Media Area	Total effective filtration area
Dust-Holding Capacity	Ability to retain dust during operation
Pleat Depth	Depth of media folds
Frame Material	Galvanized steel, aluminum, plastic or cardboard

Pleated Air Filter Media

Different types of media can be used depending on the filtration efficiency and application.

Common materials include:

• Synthetic fiber media.
• Polyester media.
• Nonwoven media.
• Glass fiber media in selected higher-efficiency designs.
• Advanced low-pressure-drop media.

Pleated Air Filter Frame Materials

Common frame options include:

• Galvanized steel.
• Aluminum.
• Plastic.
• Cardboard for selected disposable HVAC filters.

The frame material should be chosen according to humidity, temperature, installation design and required mechanical strength.

Common Pleated Air Filter Depths

Pleated filters can be manufactured in different depths depending on the system and required media area.

Common configurations may include:

• 25 mm.
• 45–50 mm.
• 90–100 mm.
• Other custom depths.

Actual dimensions should always be confirmed against the existing filter housing or equipment specification.

Custom Size Pleated Air Filters

HVAC equipment does not always use standard filter dimensions, particularly in older AHUs or imported systems.

VIETPHAT supports Pleated Air Filters according to customer requirements including:

• Width.
• Height.
• Depth.
• Filter efficiency.
• Rated airflow.
• Filter media.
• Frame material.
• Pleat configuration.
• Required quantity.

How to Select Pleated Air Filters

1. Identify the Filtration Stage

Determine whether the filter will be used as a pre-filter, primary filter, medium-efficiency filter or fine filter.

2. Determine the Required Efficiency

Select the filtration performance based on air-quality requirements and downstream equipment.

3. Verify Dimensions

Measure Width × Height × Depth accurately to minimize air bypass around the filter.

4. Check Rated Airflow

The filter should operate within its recommended airflow range.

5. Evaluate Pressure Drop

The available fan static pressure should be sufficient to overcome the resistance of the complete filtration system.

6. Consider Dust Loading

For high-dust environments, a larger media area and suitable dust-holding capacity can reduce replacement frequency.

When Should Pleated Air Filters Be Replaced?

Pleated filter replacement should be based on actual operating conditions rather than only on a fixed calendar interval.

Replacement should be considered when:

• Pressure drop reaches the defined maintenance limit.
• Airflow decreases significantly.
• The media becomes heavily loaded.
• Pleats collapse or become damaged.
• The frame becomes distorted.
• The filter reaches the maintenance interval specified by the facility.

Can Pleated Air Filters Be Washed?

Most Pleated Air Filters are designed as disposable products and should not be washed.

Water or aggressive cleaning can:

• Damage the media fibers.
• Distort pleats.
• Remove binders or treatments.
• Change filtration efficiency.
• Increase the risk of media failure.

Only filters specifically designed as washable should be cleaned and reused.

Life-Cycle Cost of Pleated Air Filters

The lowest purchase price does not always result in the lowest total operating cost.

Life-cycle considerations include:

• Initial pressure drop.
• Average operating pressure drop.
• Dust-holding capacity.
• Service life.
• Replacement frequency.
• Maintenance labor.
• Fan energy consumption.
• Impact on downstream filter life.

Pleated Air Filter Supplier in Vietnam – VIETPHAT

VIETPHAT supplies Pleated Air Filters for HVAC systems, AHUs, FCUs, Fresh Air Units, commercial buildings, industrial facilities and cleanroom pre-filtration.

We support filter selection based on dimensions, filtration efficiency, rated airflow, pressure drop, media construction and actual operating conditions.

VIETPHAT Pleated Air Filter Product Range

• Pleated Pre Filters.
• Pleated Panel Filters.
• G4 Pleated Filters.
• M5 Pleated Filters.
• Medium Efficiency Pleated Filters.
• Fine Pleated Filters.
• Mini-Pleat Filters.
• Pleated Filters for AHUs.
• Pleated Filters for FCUs.
• Pleated Filters for Fresh Air Units.
• Custom Size Pleated Air Filters.

Applications of VIETPHAT Pleated Air Filters

• HVAC systems.
• Air Handling Units.
• Fan Coil Units.
• Fresh Air Units.
• Ventilation systems.
• Commercial buildings.
• Hotels.
• Shopping centers.
• Hospitals.
• Data centers.
• Electronics factories.
• Semiconductor facilities.
• Pharmaceutical plants.
• Food processing facilities.
• Industrial factories.
• Cleanrooms.

Frequently Asked Questions About Pleated Air Filters

What Is a Pleated Air Filter?

A Pleated Air Filter uses filter media folded into pleats to increase filtration surface area within a compact filter frame.

Are Pleated Air Filters Better Than Flat Filters?

Pleated filters generally provide more media area and may offer greater dust-holding capacity than flat filters of similar face size, but actual performance depends on the filter design and media.

Is a Pleated Air Filter a Pre Filter?

It can be. Pleated describes the construction, while pre-filter describes the filtration stage. Pleated filters may also be used at medium or fine filtration levels.

Is a Pleated Filter the Same as a HEPA Filter?

No. Pleated refers to the media configuration. HEPA refers to a high-efficiency filtration classification. Some HEPA filters use mini-pleat construction, but most HVAC pleated filters are not HEPA filters.

What Is a G4 Pleated Filter?

G4 is a former EN 779 coarse-filter classification commonly used for pleated pre-filters in HVAC and AHU systems.

Can Pleated Air Filters Be Used Before HEPA Filters?

Yes. Pleated filters are frequently used upstream of fine and HEPA filters to reduce dust loading and extend downstream filter service life.

Can Pleated Air Filters Be Manufactured in Custom Sizes?

Yes. Many pleated filter configurations can be supplied according to the dimensions, efficiency and airflow requirements of existing HVAC equipment.

What Information Is Required for a Pleated Air Filter Quotation?

Please provide Width × Height × Depth, required filtration efficiency, airflow if available, media type, frame material, quantity and application.

Contact VIETPHAT for Pleated Air Filters

For consultation or quotation for Pleated Air Filters for HVAC, AHU, FCU, commercial, industrial and cleanroom applications, please contact VIETPHAT:

• Zalo / Hotline: 0971 344 344
• Sales: 0827 077 078
• Sales: 0829 077 078
• Email: sales@vietphat.com
• Website: www.vietphat.com