What Is a Panel Filter Tested To? A Guide to Basic HVAC Filter Ratings

Panel filters can look similar at a glance, but the numbers on a supplier data sheet tell you far more than the frame size or media colour. If you are comparing options for a home system, a commercial site or a plant room, it helps to know what was actually tested, which standard was used, and what the rating does and does not tell you.

At Total Air Filtration, a family-owned air filter manufacturer and supplier in Hillcrest, Brisbane QLD, we often help customers read past the headline rating and check the details that matter in practice. The right choice depends on the equipment, the dust load, the maintenance access, and the filter performance your system is designed around.

What panel filters are usually tested for

A panel filter is generally tested to measure how well it removes particles from air under defined laboratory conditions. The exact test depends on the standard or rating system the supplier uses.

Common things a data sheet may show include:

• •Initial particle capture or efficiency
• •Final resistance or pressure drop
• •Dust-holding capacity
• •Airflow resistance at a stated velocity
• •Media classification under a standard such as EN 779, ISO 16890 or AS 4260, depending on the product

This is why two filters that look alike can perform differently. The media type, pleat spacing, frame construction and sealing all affect airflow and service life.

Why the test method matters

A rating only makes sense when you know how it was measured. Some standards focus on average particle size capture, while others measure performance across particle size ranges or under defined loading conditions.

For example:

• •MERV is a rating used in ASHRAE test methods and is common on many supplier sheets
• •EN 779 classes such as G3, G4, F5 to F9 are still widely used in Australia, although EN 779 has been superseded by ISO 16890
• •ISO 16890 classifies filters by particle size range, which can be more informative when comparing general ventilation products

These systems do not convert directly. A supplier may try to summarise them side by side, but you should treat that as guidance only, not a direct equivalence.

Reading a supplier data sheet properly

A good data sheet should tell you more than just the rating code. If you are comparing panel filters, look for the test basis and the operating conditions behind the figures.

Check the standard and the stated conditions

Before comparing products, confirm:

• •Which standard was used for the test
• •Whether the efficiency is an initial value, average value, or classification band
• •The airflow or face velocity used for the test
• •The pressure drop at the stated airflow
• •Whether the product is intended for pre-filtration, general HVAC use, or a specific application

If the data sheet is vague, ask the supplier for the test basis in writing. The same wording can mean very different things depending on the standard.

Look beyond the headline rating

The rating code is only one part of the picture. Practical details often matter just as much:

• •Frame material: cardboard, galvanised steel, plastic or aluminium
• •Media type: synthetic, glass fibre or other specialist media
• •Pleat depth and spacing: affects dust loading and airflow resistance
• •Seal quality: poor sealing can let air bypass the media
• •Moisture resistance: important in some plant rooms and coastal environments

If you need a custom size, check whether the supplier can make to measurement rather than forcing an off-the-shelf fit. Our how to measure an air filter guide is a useful starting point.

Common basic HVAC ratings you may see

MERV ratings

MERV ratings are widely used on HVAC filter data sheets. A higher MERV number generally indicates finer particle capture under the test method used, but the rating does not tell you everything about how the filter will behave in your system.

When reviewing a MERV-rated panel filter, pay attention to:

• •The airflow the rating was based on
• •Initial and final resistance values
• •Whether the filter is intended for your system’s fan capacity and space constraints

A higher rating is not automatically better if the system is not designed for the added resistance.

EN 779 classes

You may still see EN 779 classes such as G3, G4, F5, F6, F7, F8 and F9 on some products in Australia. These are familiar shorthand in the market, especially for panel and bag filters.

Because EN 779 has been superseded by ISO 16890, it is best to use the class as a reference point only and read the full data sheet rather than relying on the label alone.

ISO 16890

ISO 16890 is more detailed because it classifies performance against particle size fractions. That can be useful when comparing general ventilation filters, especially where the supplier provides clear labelling for ePM1, ePM2.5 and ePM10 performance.

If you are sourcing for a commercial site, ask for the exact classification and the conditions used during testing so you can compare like with like.

What panel filter ratings do not tell you

A rating is useful, but it is not the whole story. It does not tell you:

• •How dirty your site air is
• •How often the filter will need inspection
• •Whether the fan and casing can handle the resistance
• •How well the filter will seal in your specific frame
• •Whether the filter is suitable for a special duty environment

Inspection frequency depends on the system, the site conditions and the dust load. Follow the filter and equipment manufacturer instructions, and monitor pressure drop where gauges are fitted. That is usually the most reliable way to know when a filter is approaching the end of its useful service life in your application.

Special cases: HEPA and washable filters

For higher-efficiency applications, you may see HEPA filters specified instead of standard panel filters. Under EN 1822, H13 is at least 99.95% efficiency and H14 is at least 99.995% efficiency at the most penetrating particle size, or MPPS. Those figures are specific to the standard and should not be mixed up with general HVAC ratings.

Some filters are designed to be washable - check the product instructions. Do not assume a filter can be cleaned and reused just because it looks sturdy. The media, frame and seal design all matter, and washing the wrong product can damage it or change its performance.

If you are working to a project brief or coordinating with a mechanical services engineer, site requirements should be confirmed against the design intent and any relevant application needs, including AS 1668.2:2024 where ventilation requirements apply.

Choosing the right panel filter for your site

If you are comparing options, start with the practical questions first:

• •What is the filter’s actual size and fit?
• •What standard was used to test it?
• •What airflow and pressure drop were used in the data sheet?
• •Does the system need a low-resistance pre-filter or a finer general ventilation filter?
• •Is the frame and media suited to the environment?

For homes, ease of fit and sensible airflow matter. For commercial buildings and industrial sites, the right answer may also depend on access, dust loading, maintenance schedules and the broader system design. If you are planning an upgrade or replacement, it can also help to review our products or custom air filters if standard sizes are not suitable.

Need help comparing panel filters?

If you are not sure how to interpret a supplier sheet, Total Air Filtration can help you compare ratings, sizes and construction details so you can choose a filter that suits your system. We supply and make filters for a range of applications from our Brisbane base, and we can also support ongoing maintenance through filter servicing and commercial filter servicing.

Call 07 3800 3448 or request a quote. If you’d like to discuss a specific site, you can also contact us or view the industries we supply.