What Is a Media Air Cleaner, and Is a Cabinet Upgrade Worth It?

A media air cleaner is a metal cabinet installed in the return air duct, before the furnace and air handler, that holds a deep pleated filter, typically 4 to 5 inches thick, according to media air cleaner maker Field Controls. It suits homes that want a thicker filter than a standard 1-inch slot allows, and it's installed by an HVAC contractor. The biggest day-to-day difference is maintenance: the filter is usually replaced once a year (AprilAire rates its media filters for 12 months) instead of every few months.

What Is a Media Air Cleaner?

A media air cleaner is a metal cabinet that houses a deep media filter in the return air duct, ahead of the furnace and air handler. It does the same job as a standard filter slot, but holds a much deeper filter.

How a media air cleaner works in your return duct

A media air cleaner works by sitting in the return duct, so air passes through its filter before reaching the furnace blower and air handler. Field Controls describes it as a metal cabinet that houses a media air filter, placed in the return air duct before the furnace. Every time the system fan runs, the return air goes through the cabinet's filter first.

Media air cleaner vs a standard 1-inch filter

A media air cleaner differs from a standard 1-inch filter in filter depth, service life and installation. A 1-inch filter slides into a slot; a media air cleaner is a cabinet that a contractor installs in the ductwork. For a closer look at depth, you can compare 1-inch and 4-inch filters.

The table below sets the two side by side.

Table 1. 1-Inch Filter Slot vs Media Air Cleaner

Is a Media Air Cleaner Worth It?

A media air cleaner is worth it when your home goes through 1-inch filters quickly and your system can handle a cabinet. It isn't worth it if there's no room in the return or the system can't take the extra pressure drop.

When a cabinet upgrade makes sense

A media cabinet upgrade makes sense when conditions in your home shorten the life of 1-inch filters. Filtrete says to change filters more often when you have:

• Construction or sanding in the home.

• Pets.

• Smokers.

• A fan that runs continuously.

In those homes, a media filter rated for 12 months means far fewer filter changes than a 1-inch filter rated for at least every three months.

When to skip it

Skip a media air cleaner if your system can't accommodate the cabinet or the filter's pressure drop. The DOE Building America Solution Center (PNNL) notes that systems must accommodate a filter's pressure drop. A contractor checks this before installing. Reasons to skip include:

• There's no room in the return duct for a cabinet.

• The system can't take the added pressure drop.

What installation involves

Installing a media air cleaner means a contractor fits the cabinet into your return ductwork. AprilAire states its Model 2210 is compatible with systems in basements, attics, closets and more. Once it's in, changing the filter is a homeowner task.

Can You Put a HEPA Filter in Your HVAC System?

A HEPA filter usually can't go straight into your HVAC return slot, because it typically adds too much pressure drop for the main return. HEPA filtration in a home system is usually done with a bypass instead.

Why HEPA rarely drops into the return slot

HEPA rarely drops into a return slot because, according to PNNL, a HEPA filter typically adds too much pressure drop in the main return. The EPA adds that installing a higher-efficiency or HEPA filter in ducts would probably require sheet-metal modifications and often a more powerful fan. For more on HEPA itself, see HEPA filters explained.

How a HEPA bypass system works

A HEPA bypass system works by connecting between the supply and return plenums and filtering a portion of the air, according to PNNL. Because only part of the airflow goes through it, the HEPA filter doesn't restrict the main return. A media cabinet, by contrast, filters all the return air.

Media cabinet or HEPA bypass?

A media cabinet filters all the return air with a MERV-rated filter, while a HEPA bypass filters part of the air with a HEPA filter. If you only need cleaner air in one room, portable HEPA air purifiers are another option.

Here's how the three options compare.

Table 2. Media Cabinet vs HEPA Bypass

Which Replacement Filter Fits Your Media Air Cleaner?

The replacement filter that fits your media air cleaner depends on the cabinet's brand and model number. Check the model label on the cabinet, or the part number on the old filter, before you order. You can browse media air cleaner replacement filters once you know it.

AprilAire air cleaners and filters

AprilAire air cleaners use the AprilAire 210, 410, 213 or 413 filter, depending on the model. AprilAire is moving these filters to its TriPure line: the 210 is being replaced by the UK211, the 410 by the UK411 and the 213 by the UK213, with free one-time upgrade rails. Match the model number on your cabinet label to the table below.

Table 3. AprilAire Cabinets and Filters

Honeywell (Resideo) media air cleaners

Honeywell media air cleaners use the Honeywell FC100A1037 filter, a 20 x 25 inch MERV 11 replacement media filter. Resideo lists it for the Honeywell Home F25, F27, F35, F100, F150 and F200 air cleaners, and notes its low static pressure drop. DFS carries the genuine Honeywell FC100A1037.

Lennox, Carrier, Bryant and Trane cabinets

Lennox, Carrier, Bryant and Trane media cabinets each take a filter identified by an OEM part number. Match the part number printed on your old filter to the table below. DFS stocks Tier1 replacements for these parts, and you can also shop 5-inch air filters.

Table 4. Other Cabinets: OEM Part to DFS Replacement

How to avoid proprietary filter lock-in

You can avoid proprietary filter lock-in because compatible replacements exist for the major media cabinets. Table 4 lists Tier1 options by OEM part number. Filtrete Refillable frames come in nominal 16x25x4 and 20x25x4 sizes, and Filtrete states they are designed to fit Honeywell, Lennox, Carrier, Bryant and other cabinets.

Whichever route you take, match the cabinet's listed filter size and part number exactly, so the filter seals and air doesn't bypass it.

How Often Should You Replace a Media Air Cleaner Filter?

Most media air cleaner filters are rated for replacement every 12 months, but check yours monthly and change it sooner if needed. Follow the interval from your filter or cabinet maker.

Manufacturer replacement intervals

Media air cleaner filter intervals come from the filter or cabinet maker, and most are 12 months. Where no interval was published, follow the filter label or your air cleaner manual.

Table 5. Replacement Intervals by Filter

Signs to replace it sooner

Replace a media air cleaner filter sooner than its rating when your home puts extra load on it. ENERGY STAR recommends checking the filter every month. Filtrete says to change filters more often with:

• Construction or sanding in the home.

• Pets.

• Smokers.

• A continuously running fan.

To stay on schedule, set up Auto-Ship reminders.

Frequently Asked Questions

Is a media filter the same as a 4-inch filter?

A media filter is the deep pleated filter that goes in a media air cleaner cabinet, and most are 4 to 5 inches deep. The cabinet model decides the exact size, so a media filter for one cabinet may not fit another. Check the cabinet label or the old filter before ordering.

Can you clean an AprilAire filter?

AprilAire directs owners to replace its media filters every 12 months and does not list cleaning as maintenance. Plan on swapping the filter rather than cleaning it. For washing filters in general, see can you wash a furnace filter.

Does a media air cleaner reduce airflow?

Every filter adds some pressure drop, but the EPA notes that thicker filters generally create less static pressure than thinner ones. A contractor sizes the cabinet to your system so it can accommodate the filter's pressure drop. Keep the filter changed on schedule, since an overdue filter may restrict airflow.

Can I install a media air cleaner myself?

Media air cleaners are installed in the return ductwork, usually by an HVAC contractor. The cabinet has to fit the duct and suit your system's airflow, which is a contractor's call. Once it's installed, replacing the filter is a homeowner task.

Do whole-house air cleaners really work?

Whole-house air cleaners filter the air that passes through your HVAC system while the fan runs. How much air they clean depends on how long the fan runs and the filter's MERV rating. A media cabinet filters all the return air, while a HEPA bypass filters a portion of it.

Sources

• Field Controls, "What Is a Media Filter?" (definition)

• AprilAire 210, 410 and 213 product pages; AprilAire Model 2210 page

• Resideo FC100A1037/U product page

• Filtrete (3M) FAQ (intervals, conditions, Refillable)

• DOE Building America Solution Center (PNNL), High-MERV Filters

• EPA, Residential Air Cleaners, 2nd ed.

• EPA Indoor airPLUS filtration bulletin

• ENERGY STAR Guide to Energy-Efficient Heating and Cooling