Waterfurnace Geothermal 24x28x1 MERV 11 Airguard Air Filter (4PK)

The 2428WF is manufactured by Airguard for WaterFurnace and is considered by WaterFurnace to be the OEM replacement 1" MERV 11 air filter for their Geothermal Comfort Systems that use a 24 x 28 x 1 pre-filter.

The replacement filters used with WaterFurnace units that use a 24 x 28 x 1 pre-filter must use a filter that is a full 24" x 28".  If you use a smaller filter sold by other manufacturers, your filter will not seal properly, and you could get unfiltered air leaking around the edge of the filter, this is called bypass. The 2428WF MERV 11 air filter is approximately 24" x 28" x 1" and is the size recommended by WaterFurnace for a proper fit.

Common WaterFurnace Geothermal Heat Pump Models that use the 24 x 28 x 1 MERV 11 pre-filter:

6 Series Vertical Units: 022, 030, 026

The 2428WF is made of 100% synthetic fibers that are needled together and then electro statically charged.  The needled fibers create a dense mat that produces a MERV 11 rating and higher mechanical efficiency at a lower air resistance than other pleated filters. 

The manufacturer suggested replacement interval is 4 to 6 months, depending upon conditions and lifestyle.

Please refer to your unit's Owner's Manual for instructions on changing your furnace's air filter.