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21x23.25x1 Air Filter Merv 8
21x23.25x1 AC Filter Merv 11
21x23.25x1 Furnace Filter Merv 13
21x23.25x1 Filter Merv 13 Titanium
21x23.25x1 Filter Merv 10 Carbon
21x23.25x1 Filter Merv 8 Carbon 21x23.25x1 Filter Merv 8 Carbon
Protects All Against
  • Pollen protection
  • Dust protection
  • Mold protection
  • Dust Mites protection
    Dust Mites
  • Bacteria protection
  • Pet Dander protection
    Pet Dander
  • Smoke protection
  • Viruses protection
  • Cooking Smoke protection
  • Odor protection
  • Smog protection
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21x23.25x1 Air Filter

AC Furnace Air Filter 21x23.25x1 -Inches

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Odor Eliminator

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Product Description

Item Model Number: FKFB21X23.25A
Brand: Filter King
Filter size: 21x23.25x1
Actual Size: 21 x 23.25 x .75
1-Inch Filter
MERV 8 Filter Rating
Protection From: Pollen, Dust, Mold, Dust Mites, Bacteria, Pet Dander, Smoke, Viruses
Residential / Commercial Use

Manufactured in the US

Why Buy Air Filters From Filter King?


In comparison to fiberglass filters, 21x23.25x1 pleated air filters are at least 20 times more effective. All Filter King air filters are made in the US.


Filters frames are made out of heat resistant paperboard with horizontal grid supports. Able to withstand temperatures of up to 200° F and resistant to moisture, the paperboard frames do not support microbial growth and outperforms traditional cardboard frames.


Chemical free, electrostatically charged synthetic polyester media is pleated, maximizing the surface area, to capture a high number of airborne particles as small as 0.3 microns with low air flow resistance. To increase durability, the media is supported with a corrosion resistant steel wire.

21x23.25x1 Air Filter Reviews

What MERV Rating should I choose?

How Often to Change Your 21x23.25x1 Air Filter?

Filter King AC & furnace filters aren’t the typical fiberglass filters that need to be replaced every 30 days. Our filters can typically be used for 3 to 5 months before requiring to be changed. Naturally, a variety of things influence filter lifespan.

Some of the factors that influence your filter’s life include outdoor air quality, whether pets are in the home, and how well your HVAC system is maintained.

Your air filter becomes clogged over time by trapped particles, preventing airflow. The efficiency of the HVAC filter declines. Your system must work harder to heat and cool your home. The extra strain on the HVAC system causes higher energy bills. Regular home air filter replacements can prevent expensive system repairs or replacements down the road.

You should change your filter more frequently if you notice:

  • Household dust build-up
  • The air isn’t cooling as is used to
  • There’s more dust near the air vents
  • A dirty filter surface
  • Higher energy bills
  • Burning smells near your HVAC system.

21x23.25x1 Air Filter

Filter King 21x23.25x1 size air filters are valuable tools used to keep the air coming into your home clean. Our air filters are ergonomically designed to keep airflow coming through clean of any airborne irritants. The tight mesh weaving is loose enough to allow the process to continue until the filter is completely covered in particles. You need to swap out these dirty air filters for new ones, before they start causing several problems throughout your home.

The air system in your home only grow dirtier over time as they continue to become covered in captured particles. The filters become so dirty that they become unable to properly process any incoming airflow. Without fresh air, your home will begin to suffer from dryness and stagnation over time. Your air systems will try to push the airflow through the blockage but that may result in further problems. The systems become strained and use more energy as they increase their efforts, possibly leading to mechanical damage and an increase in billing over time.

The air filters in your home need frequent replacement if the air is to remain comfortable to breathe in. Filter King is ready and able to deliver fresh new 21x23.25x1 size air filters to your home. Orders of two or more filters are shipped for free and delivered regularly if you use our subscription option. The filters we provide have a MERV (Minimum Efficiency Reporting Value) rating of eight and block out particles like:

  • Pollen
  • Dust
  • Mold
  • Dust Mites
  • Bacteria
  • Pet Dander
  • Smoke
  • Viruses

21x23.25x1 Furnace Filters

The air filters in your home are usable for a variety of systems including your furnace systems. The furnace filters clean out incoming airflow and make sure that the heated air is not bringing any harmful particles. The filters become dirtier over time and require replacement, or they cause temperature problems throughout the system. The heated airflow is stopped and begins to build up which eventually causes mechanical damage. Order new air filters today and ensure your home’s heated airflow enters without any issues.