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12.5x21x1 Air Filter Merv 8
12.5x21x1 AC Filter Merv 11
12.5x21x1 Furnace Filter Merv 13
12.5x21x1 Filter Merv 13 Titanium
12.5x21x1 Filter Merv 10 Carbon
12.5x21x1 Filter Merv 8 Carbon 12.5x21x1 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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12.5x21x1 Air Filter

AC Furnace Air Filter 12.5x21x1 -Inches

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Odor Eliminator

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Product Description

Item Model Number: FKFB12.5X21A
Brand: Filter King
Filter size: 12.5x21x1
Actual Size: 12.5 x 21 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, 12.5x21x1 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.

12.5x21x1 Air Filter Reviews

What MERV Rating should I choose?

How Often to Change Your 12.5x21x1 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.

12.5x21x1 Air Filter

Filter King 12.5x21x1 size air filters are necessary components to any standard air system to keep the incoming airflow clean. There is a large range of irritants that are capable of entering your home via airflow. Your home may have any level of pollutants or allergens in the surrounding air able to quickly drop its indoor air quality. To avoid airborne issues for a home, it is best to install new air filter regularly to avoid any issues with the airflow in a home. Air filters are capable of cleaning the air, but they also become a problem themselves as they become dirtier.

The air filters in your home will eventually become dirty over time, and the resulting issues will only grow worse as they become dirtier. Your air filters consist of a tight mesh weaving designed to capture passing irritants while airflow is allowed to pass through. When the mesh is covered in captured particles then the airflow is unable to pass through and cycle within a home. Your home needs consistent airflow or the resulting problems lead to dry air, stagnation, increased billing and strain on your home’s air systems.

Our 12.5x21x1 size air filters are able to fit into any accompanying air systems and help provide your home with fresh airflow. The filters rate as an eight on the MERV (Minimum Efficiency Reporting Value) scale. With that rating, the filters are able to block out a range of irritants including:

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

12.5x21x1 Air Filter Delivery

Filter King offers replacement filters at affordable prices designed to fit easily into any accompanying air systems. The air filters you order are usable upon arrival, with bulk orders of two or more shipped for free. We offer a subscription service as well, where new filters are delivered regularly to your home. Stop worrying about clean airflow and order the filters that will help keep your home smelling fresh and clean.