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Lennox Furnace Filters

Lennox Healthy Climate X0445 Air Cleaner Filter Media - 2 Pack

Size Guide

Expandable media air filter - ships like a collapsed accordion and is expanded into existing frame. Electrostatically charged disposable media captures dust mites, pollen, mold spores, pet dander and other contaminants down to 0.3 microns. Synthetic media offers large surface area for maximum dirt holding capacities with minimum air resistance. Media is certified to UL 900 standard.
  • 2 Pack
  • Nominal Size: 25" X 6" X 4"
  • Actual Size: 19-3/4" x 24-1/2" x 6-3/8"
  • Manufactured by Lennox
  • MERV 10
  • Replace every 6 months under normal use
  • Replaces Aprilaire 2200, 201

Customer Reviews

Based on 2 reviews

Sent wrong filter replaced it quickly

Easy filter change

Placing my order online was easy & the item was quickly shipped and received in just a few days. Installation instructions were with the product, but the YouTube how-to video was very useful. Taking out and installing the new filter was no problem. Price for a package of two filters was very competitive. I plan to order from this company again.

Nominal Vs. Actual Sizes: Finding the Right Air Filter Size

Buying the Correct Size Air Filter- The Most Important Thing to Know 

When you are buying your air filter online most important thing to know is Air Filters have two sizes that you need to understand the Nominal size and the Actual Size. Not understanding these numbers often leads to consumers purchasing a filter that does not fit their Furnace or HVAC system. See the complete list of Air Filters by Size Rating and Brand.

Nominal vs Actual air filter size by Atomic


Understanding Nominal Filters Size Could Save You Time and Money

Not understanding the Nominal Filter Size is the primary culprit for incorrectly purchased filters.The Nominal Size is the usually the dimensions used to Label the filter. For instance 16x20x1. These dimensions are a rounded value on the filters actual measurements. The actual measurements on this filter may be 15.5x19.5x.75, but that could vary by brand and manufacturer. So in order to make sure you have the correct size filter, especially if you are replacing with a different brand it is important to confirm the actual size on the filter. When purchasing filters on the internet the Nominal size is usually found in the product title.

Actual Filter Size- The Key to Making the Right Replacement Filter Purchase

The actual size as you might have guessed are the actual dimensions of the filter by length, width and thickness. This size is often on the filter right below the Nominal size and is usually labeled as the actual size. When you are buying a filter online the actual size is sometime in the product bullet point or the product description. If your filter does not have actual dimensions on the outside of the filter, you can measure you filter to get the correct dimensions. Some brands have a foam gasket on the outside of the filter, in this case, you will want to make sure you have a compatible actual size and that it also has the foam to ensure a snug fit. 

Lennox Air Filter X0851 with Foam strips

Examples of Nominal and Actual Sizes

 Size  Example 1  Example 2
Nominal Size 20x20x1 16x20x1
Actual Size 19.5x19.5x.75 15.75x19.75x.75


 Furnace filters should fit securely but should not have to be forced into position. If you have to force the filter into its slot, then it is probably too big. Forcing an improper filter size in a filter can cause it to buckle, damaging the filter or reducing its ability to function properly. Filters are a smaller than their slot to allow for easy replacement. Some HVAC units may need a filter with dimensions that are unique or uncommon. In these cases, a custom filter needs to be ordered.

Find Your Filter Sizes Easy in 1" Deep Filters , 2" Deep Filters, 4" Deep Filters