Coarse Air Filter G1–G4 for AHU and Industrial Pre-Filtration
Coarse air filters are used as the first filtration stage in HVAC and general ventilation systems. Their main job is to capture larger dust, lint, fibres and visible airborne debris before the air reaches coils, fans, medium filters, compact filters or HEPA filters.
This G1–G4 coarse air filter range is designed for projects where the air contains a higher dust load and the buyer needs a practical, low-resistance pre-filter. It is commonly used in AHU fresh air intake sections, return air systems, warehouse ventilation, parking garages and general industrial air handling units.
For contractors and system integrators, this product is not selected only by filter grade. Size, frame strength, airflow, pressure drop, installation track and replacement method all need to match the actual project.
Installation Steps (Step-by-Step)
Shut down & lock out the unit; confirm power is off.
Verify specifications: size, thickness, frame type, and gasket match the housing.
Airflow direction: Follow the arrow on the frame. If none, install with the coarse/reinforced side facing upstream.
Seal & secure: Ensure a tight perimeter fit (use gaskets/clamps) to prevent bypass leakage.
Spacing & support: Keep even spacing across multiple filters; for large sizes or high face velocity, add support grids/retainers to prevent sagging.
Re-close & check: Close access panels, check for abnormal noise/leakage, then restart.
Construction & Material Options
Our coarse filters are intentionally simple in structure, but we pay a lot of attention to material selection and consistency.
Filter Media
We typically use:
Synthetic fibre / non-woven fabric as the main media
Good dust holding capacity
Stable in normal humidity
Available in different weights for G1–G4 grades
Other media (such as metal mesh or fiberglass) can be used in special designs, but the standard coarse panels are based on synthetic non-woven.
Frame Choices
Depending on where the filter will be used, we can supply:
Galvanized steel frame – for industrial systems and places with rough handling or higher airflow.
Aluminium frame – lighter, corrosion-resistant, convenient for many HVAC units.
Cardboard frame – economical option for large-volume projects and comfort HVAC systems.
Media is bonded or clamped into the frame to avoid bypass. For some models we add a support mesh so that the media stays flat and doesn't deform during operation.
Where Customers Actually Use Coarse Air Filters
AHU Fresh Air Intake
Outdoor air can carry dust, insects, fibres, leaves and larger airborne debris. A coarse filter at the intake side helps reduce the dust load before air reaches coils and downstream filters.
01
Return Air Sections
In commercial buildings, return air may contain lint, fibres and general room dust. A coarse panel filter can help keep the air handling section cleaner and reduce maintenance pressure on later filter stages.
02
Warehouses and Logistics Facilities
Warehouses, loading areas and logistics hubs often have heavy dust movement from cartons, pallets, vehicles and open doors. Coarse air filters are commonly used as a practical first-stage filter in these environments.
03
Parking Garages and Underground Car Parks
Parking areas usually need a durable pre-filter that can handle visible dust and general debris. The filter should be easy to replace and strong enough for regular maintenance work.
04
General Industrial Ventilation
For non-critical production areas, workshops and utility rooms, coarse filters are often used to protect ventilation equipment and extend the service life of downstream filters.
05
Production process
A:)Mould
G:)Powder coating
B:)Forging
H:)Checking
C:)Die-casting
I:)Assambling
D:)Processing
J:)Checking
E:)Polishing
K:)Packing
F:)Acid washing
Certifications
Our coarse air filter meet stringent international standards, including ISO 9001 certification and CE compliance. These certifications reflect our commitment to quality and reliability.
What Matters Most with Coarse Filters
When buyers discuss coarse filters with us, they usually focus on a few core points rather than very detailed lab data:
1
●Can they handle the dust load in my environment?
●We look at your site (warehouse, plant, garage, etc.) and suggest appropriate G-grade and media weight.
2
●Will they protect my downstream filters and coils?
●The idea is to keep the big particles in the primary filter so that more expensive G4/F5/F7 filters and equipment stay cleaner for longer.
3
●How often will I have to change them?
●We share typical intervals seen in similar projects (3–6 months for many coarse applications) and refine based on your actual dust load.
4
●Are they easy to install and dispose of?
●Frames and sizes are made to match standard filter tracks. Used filters can be removed quickly and disposed of as general waste in most regions, subject to local regulations.
Packaging and Transportation
For coarse filters, packaging has to protect the frame and media without adding unnecessary cost:
Panels are typically stacked and wrapped in protective film or cartons, depending on size and frame type.
For export and larger orders, we palletise and strap the cartons to keep them stable during shipping.
Mixed shipments with other filter types (bag filters, compact filters, metal mesh filters, etc.) are possible so distributors and contractors can consolidate different items in one load.
We're used to working with both project-based shipments and regular replenishment orders, so if you have a particular way you like filters packed and labelled, we can usually align with that.
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