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21x23x1 Air Filter Merv 8
21x23x1 AC Filter Merv 11
21x23x1 Furnace Filter Merv 13
21x23x1 Filter Merv 13 Titanium
21x23x1 Filter Merv 10 Carbon
21x23x1 Filter Merv 8 Carbon 21x23x1 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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21x23x1 Air Filter

AC Furnace Air Filter 21x23x1 -Inches

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Odor Eliminator

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Product Description

Item Model Number: FKFB21X23A
Brand: Filter King
Filter size: 21x23x1
Actual Size: 21 x 23 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, 21x23x1 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.

21x23x1 Air Filter Reviews

What MERV Rating should I choose?

How Often to Change Your 21x23x1 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.

21x23x1 Air Filter

Filter King 21x23x1 size air filters are vital parts of any home air systems and their ability to clean out incoming airflow. The filters in your home consist of a tight mesh weaving that allows air to travel through while any irritants become trapped or absorbed. Your home’s air quality rises during the process as clean air filters throughout its rooms. However, your air filters will become dirtier over time and eventually start creating problems for your home if they are not frequently replaced.

When the air filters in your home’s air systems are not frequently replaced then they start to become dirty and ineffective. Dirty air filters are a problem for your home due to their tendency to block out any fresh air that is pumped in by your systems. When your home is unable to receive fresh air, then that leads to issues of dryness and stagnation. Your air systems will try to push airflow past the blockage, but that will lead to strain that severely affects their integrity. A strained system is more likely to suffer mechanical damage and cause your energy billing to rise.

Your home air systems need new air filters put in place in order to keep the airflow coming in clean. Filter King offers new 21x23x1 size air filters ready for purchase and able to be used upon arrival. We offer a delivery service with a subscription option to have new filters regularly delivered right to your door. Orders of two or more filters are shipped for free. The filters themselves have a MERV rating of eight and block out irritants like:

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

21x23x1 Furnace Filters

The furnace filters in your home have the important job of keeping heated airflow clean before it enters your home. However, the heated airflow is also capable of becoming blocked and causing issue when the filters are dirty. When heated airflow is blocked, that causes a rise in temperatures that could cause mechanical damage over time. The heated airflow is also unable to warm your home, causing temperature fluctuations. Order new air filters today and enjoy fresh airflow throughout your home with new air filters installed.