WaterFurnace Geothermal 30x32x1 OEM Airguard MERV 10 Air Filter (4-Pack) 30321WF

The WaterFurnace 30321WF is the OEM replacement 1" pre-filter manufactured by Airguard for WaterFurnace Geothermal Systems. It is the factory-recommended 30" × 32" × 1" MERV 10 filter for units that require a full-size pre-filter.

Update: The MERV 11 version has been discontinued. WaterFurnace now supplies this MERV 10 model to meet airflow and efficiency requirements.

Why Full-Size Filters Matter

This genuine 30321WF is a true 30" × 32" filter for a proper seal that helps prevent air bypass (unfiltered air leaking around undersized filters). A smaller nominal filter will not seal correctly.

Filter Media & Performance

Constructed of 100% synthetic, needled fibers that are electrostatically charged to capture particles efficiently while maintaining low airflow resistance and system performance.

Replacement Interval

Replace every 4–6 months, depending on operating conditions and household environment. Refer to your unit’s Owner’s Manual for installation and maintenance.

What’s Included

Quantity: 4 filters per package.

Specifications

Note: Always verify sizing and replacement procedures in your WaterFurnace Owner’s Manual.