Media Pads, Carbon Bags and V-Banks: Which Carbon Format Fits Your System?

If you are planning odour control in a commercial HVAC system, the carbon format matters as much as the carbon itself. Media pads, carbon bags and V-banks all use activated carbon, but they suit different housings, airflow paths and maintenance access arrangements.

For mechanical contractors and facility managers, the practical question is usually not “which carbon filter is best?” but “which format will actually fit the plant, move air properly and address the odour source?”

Start with the system, not the carbon

Carbon filters are used for odour adsorption, not general dust filtration. That means the first step is to look at how air moves through the unit, how much space is available for the filter section and what the site is trying to control.

Before selecting a format, check:

• •the available filter face area and housing depth
• •whether the system takes flat media, bag-type elements or V-bank cartridges
• •the direction of airflow through the filter bank
• •access for changeout and inspection
• •whether prefiltration is already in place upstream
• •the odour source, such as kitchens, amenities, waste rooms, plant rooms or process areas

If you are not sure of the current opening size or frame details, how to measure an air filter is a useful starting point before ordering replacements or discussing a custom option.

Media pads: simple, shallow and suited to tight housings

Media pads are the most compact of the common carbon formats. They suit systems where depth is limited and the filter section was originally designed for flat inserts rather than deeper cartridges.

Where media pads work well

Media pads are often chosen when:

• •the housing has limited depth
• •the system uses slide-in frames or panels
• •the airflow path is straightforward and even across the face
• •the application needs a basic odour control stage in a smaller footprint

They can be a practical option for plant rooms, small mechanical systems and retrofit jobs where there is no room to convert the filter section to a deeper format.

The trade-off is that a shallow format usually gives less carbon bed depth than a larger cartridge or bag arrangement. That makes media pads better suited to lighter odour loads or to systems where the air has already been conditioned and prefiltered.

Points to watch

With media pads, pay close attention to:

• •bypass around the frame if the sealing arrangement is poor
• •even loading across the filter face
• •available access for regular inspection
• •whether the existing housing can support the pressure drop of the selected product

If you are planning a retrofit, it is worth confirming the arrangement with the mechanical services engineer or building owner, especially where the system also needs to meet site-specific ventilation requirements under AS 1668.2:2024.

Carbon bags: more depth for odour-heavy applications

Carbon bags are commonly used where the system can accommodate a deeper filter section and where odour control demand is more noticeable. The bag shape increases carbon contact area compared with a flat pad, which can make them a better fit for tougher air streams.

Why contractors choose carbon bags

Carbon bags are often considered when:

• •the housing depth allows a deeper filter stage
• •the airflow path can handle a bag-style element without crowding adjacent components
• •the application produces stronger or more persistent odours
• •there is a need to improve contact time without changing to a cartridge bank

Typical applications can include kitchens, food preparation areas, waste handling spaces, loading docks, amenities and some light industrial environments where odour transfer is a concern.

Because the bag profile is deeper than a pad, it can offer a better balance between airflow capacity and odour control in systems that have enough room to use it properly. That said, bag filters still need suitable upstream dust control to avoid premature loading of the carbon section.

Airflow and maintenance considerations

When specifying carbon bags, check:

• •the filter chamber depth and access clearance
• •whether the bag shape will maintain stable airflow through the face area
• •whether the seals and holding frame are suited to the installed format
• •if there is enough access to inspect the filter condition without dismantling surrounding plant

Inspection frequency depends on the system, site conditions and dust load. Follow the filter and equipment manufacturer instructions, and monitor pressure drop where gauges are fitted.

V-banks: larger surface area in a compact footprint

V-banks use a pleated or folded arrangement that gives more media surface area within a relatively compact housing depth. For carbon applications, that can be useful where the system needs more contact area than a flat pad can provide, but there is still limited room for a deeper bag or canister setup.

Where V-banks make sense

V-banks are often suited to:

• •central air handling units with a dedicated filter section
• •systems needing a stronger odour-control stage than a flat panel can provide
• •installations where face area and airflow distribution are already well managed
• •projects that need a more compact alternative to larger deep-bed arrangements

They are not the answer for every job, but they can be a good middle ground when the housing is space-limited and the airflow path is consistent across the bank.

When to think twice

A V-bank format may not be the best choice if:

• •the housing is too shallow for proper access and sealing
• •the airflow is uneven and likely to load one section harder than another
• •the site has heavy particulate loading without suitable prefiltration
• •the installation detail makes replacement awkward or unsafe

As with any carbon stage, V-banks rely on good system design. If the air stream is carrying too much dust, the carbon media can be masked by particle load before it does the odour-control work it was selected for.

How to match the format to the odour source

The odour source is usually the deciding factor once the housing dimensions are known. Different locations place different demands on the filter media and the airflow path.

Typical fit by application

• •Media pads: small or shallow housings, lighter odour control needs, compact retrofit jobs
• •Carbon bags: stronger odour loads, larger service spaces, systems that can accept more depth
• •V-banks: compact AHU sections needing more surface area than a flat panel can offer

In practice, many systems also need a prefilter stage ahead of the carbon media. That helps catch larger particles before they reach the odour-control filter. The right prefilter and carbon stage combination can make maintenance easier and keep airflow more stable over time.

If your project needs a non-standard size or a different frame arrangement, custom air filters can be a better path than forcing a poor fit into an existing housing.

Questions to ask before you order

A quick site check can save a lot of back-and-forth.

Ask:

• •What is the exact filter opening size and frame depth?
• •Is the airflow entering the filter evenly across the full face?
• •Is there enough space to remove and replace the element without disturbing nearby equipment?
• •Is the application mainly odour control, or does it also need particle capture upstream?
• •Are there existing gauges or access points for monitoring pressure drop?
• •Has the mechanical services engineer confirmed the arrangement where required?

If the current filter setup is worn, damaged or no longer suits the system, filter servicing or commercial filter servicing may be worth discussing alongside replacement.

Choosing the right format for your site

There is no single carbon format that suits every commercial HVAC system. Media pads suit shallow housings and simpler arrangements. Carbon bags offer more depth for stronger odour applications. V-banks can provide more surface area within a compact footprint when the housing and airflow path are right.

The best result usually comes from matching the filter format to the available space, the direction of airflow and the actual odour source, rather than choosing by habit.

Total Air Filtration is a family-owned air filter manufacturer and supplier in Hillcrest, Brisbane QLD, established 2009. We can supply standard formats or make the right fit for your system. Call 07 3800 3448 or request a quote. You can also contact us or view our products.