0502025 – JOHNSON BOX

The Johnson Box is a heavy-duty filter rack with solid metal sides, making it ideal for inline duct installations where you need an enclosed filter compartment. It holds a standard 20×25 filter and can connect directly to ductwork on both ends. Good option when you need a filter rack that doubles as a duct section.

Specs: 20″ x 25″ filter size, solid metal sides, inline or air handler mount, galvanized steel

Replaces: 0502025

Fits: Air handlers and furnaces using 20×25 filters. Universal fit for all HVAC brands.

In stock at Open To Public HVAC Parts in Dallas. We test parts at the counter before you buy. Call or text (214) 340-9421.

Specs

• TypeFilter base
• PositionReturn side, upstream of the blower and coil

What size filter base do I need?

It is sized to the furnace or air handler cabinet it bolts to, and to the filter that goes in it. A 20"W x 25"D base takes a 20x25 filter. Measure the cabinet width first - the base has to match the equipment, and the filter follows from that.

Can I put a 4 inch filter in it?

Only if the base is built for it. Some of our bases accept 1", 2" or 4" media; others are 1" only. Check the listing - a 4 inch filter will not go into a 1 inch rack no matter how you angle it.

What is the difference between a filter base and a filter rack?

A filter base is a sheet metal section that sits under the furnace and forms part of the cabinet, with the filter slot built in. A filter rack is a frame that mounts on the return side to hold a filter. Both do the same job in different places.

Why go to a 4 inch media filter?

Far more filter surface area, so it catches more while restricting airflow less, and it lasts six to twelve months instead of one to three. It needs the deeper slot, which is the whole reason to change the base.

Does the filter go in before or after the blower?

On the return side, before the blower and before the coil. That is the point of it - everything downstream stays clean.

Do you stock these?

We keep common sizes on the shelf at 10226 Plano Rd, Suite 104 in Dallas. Bring the furnace model and the cabinet width.