Koch Multi-Pleat XL11 MERV 11 Standard Capacity MERV 11 Extended Surface Pleated Panel Filter

That's the size the Multi-Pleat XL11 Standard Capacity is offered in: 20x25x4 nominal. If your air handler or filter rack is cut for a nominal 20 by 25 four inch panel, this drops straight in. It's a panel filter, so it slides into the existing track with no adapter or frame kit.

MERV 11 is the step above ordinary pleated filters, and Koch positions the Multi-Pleat XL11 specifically for hospitals, laboratories and pharmaceutical plants, commercial office buildings, and any system needing a higher degree of clean air. It also runs an Initial Dust Spot Efficiency of 45% and an Average Dust Spot Efficiency of 55 to 60% under ASHRAE 52.1. For a general medical office or lab prefilter that's the right band. If you're filtering a critical space with a downstream HEPA bank, this is your prefilter, not your final filter.

It comes down to how you schedule filter changes. Standard Capacity is the one to buy when changes are on a preventive maintenance calendar, say every quarter regardless of condition. The XL11-HC is built the same way but carries about 30% more media, which stretches filter life, so it's the pick when your changeouts are triggered by a final pressure drop reading instead of a date. Property managers running a fixed PM route are usually better off with Standard.

That fade is real on single layer charged media: as the filter dirties, the electrostatic charge dissipates and efficiency drops off. Koch built the XL11 around it with dual layer media, an upstream electrostatically enhanced E-Layer and a downstream mechanical M-Layer. As the E-Layer's charge falls off, the M-Layer carries the load, which holds performance and dust holding capacity through the service interval. That matters if you're specifying to a MERV number and expect it to still be true at month four.

Both. The XL11 is listed for commercial, industrial and residential HVAC. In a house the 20x25x4 size is a common media cabinet size, so it works as a direct replacement in a four inch residential filter cabinet as readily as it does in a commercial rooftop or air handler rack.

The Multi-Pleat XL11 carries its MERV 11 as a fractional efficiency rating under ASHRAE Test Standard 52.2, which is the current test method a spec or submittal will call for. The older 52.1 dust spot numbers are also published: 45% initial, 55 to 60% average. If you're filling out a submittal that asks for the test standard, 52.2 is the one to cite.

100% synthetic, in a dual layer construction Koch developed specifically for extended surface air filters. No cotton blend. For a facility that's had trouble with media shedding or moisture in a humid air stream, all-synthetic is the relevant detail here.