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Home / Air Filter Sizes / Lennox / 20x21x5

20x21x5 Air Filter Merv 8 20x21x5 Air Filter Merv 8
20x21x5 AC Filter Merv 11 20x21x5 AC Filter Merv 11
20x21x5 Furnace Filter Merv 13 20x21x5 Furnace Filter Merv 13
20x21x5 Filter Merv 13 Titanium 20x21x5 Filter Merv 13 Titanium
20x21x5 Filter Merv 10 Carbon 20x21x5 Filter Merv 10 Carbon

Lennox 20x21x5 Air Filters

Replacement Filter

Actual Size: 20 X 20.63 X 4.38

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1. Select Filter Quality

merv-8
Standard
MERV 8
merv-11
Good
MERV 11
merv-13
Better
MERV 13

2. Select Quantity

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Product Description

Item Model Number: FKDPFL20X21X5
20x21x5 (20 x 20.63 x 4.38) MERV 8 Filter King Replacement Filter for Lennox

Manufactured in the US

Why Buy Air Filters From Filter King?

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In comparison to fiberglass filters, 20x21x5 pleated air filters are at least 20 times more effective. All Filter King air filters are made in the US.

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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.

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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.

20x21x5 Air Filter Reviews

How Often to Change Your 20x21x5 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.