Filter King AF21x21x1-M13 Merv 13 Air Filter 21x21x1

Product Description

The FILTER KING AF21x21x1-M13 is a MERV 13 pleated air filter designed for residential and light commercial HVAC systems. With a nominal size of 21x21x1 and an actual size of 20.5 x 20.5 x 0.75 inches, it fits standard 1-inch filter slots. At MERV 13, this filter captures fine particulates including dust, pollen, mold spores, pet dander, and fine smoke particles — making it a common choice for systems where indoor air quality is a priority. HVAC technicians and building maintenance personnel typically specify this rating for improved filtration without excessive static pressure drop. This listing includes a quantity of 10 filters.

This filter is suited for residential forced-air systems and light commercial applications where a 21x21x1 nominal filter slot is present. It installs in the return air grille or air handler filter rack. The MERV 13 rating is appropriate for systems where occupant health, allergen control, or smoke mitigation are considerations. Verify that the air handler or furnace blower is rated to handle the increased resistance of a MERV 13 filter before installation — older or undersized blower motors may experience reduced airflow.

Key Features

• MERV 13 filtration rating captures fine particulates down to 1 micron
• Nominal size 21x21x1 inches fits standard 1-inch filter slots
• Actual dimensions 20.5 x 20.5 x 0.75 inches for proper fit in housing
• Pleated media construction increases surface area and filter life
• Sold in a 10-pack for routine maintenance stocking

Compatibility

Designed for HVAC systems, furnaces, and air handlers with a 21x21x1 nominal 1-inch filter slot. Verify actual opening dimensions against the filter actual size of 20.5 x 20.5 x 0.75 inches before installation.

Installation Notes

HVAC technicians and qualified service personnel should power down the air handler or furnace at the disconnect before replacing filters. Install with the airflow arrow on the filter frame pointing toward the blower. Check the existing filter frame or housing for actual clearance dimensions to confirm fit before ordering in bulk. Inspect and replace on a schedule appropriate to occupancy load and environmental conditions — MERV 13 filters may require more frequent changes than lower-rated media in high-particulate environments.