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Atomic Filters carries a wide selection of top name brands. If you do not see the Brand or items you are looking for, use our search function to find your item by part number or size. Send us a note on our contact page if you are having trouble locating you filter and we will help you find the air filter, water filter or part accessory you need. Well known Brands including Honeywell, Carrier, Lennox, Samsung, and Whirlpool are available as well as compatible replacement Furnace filters and Water filters. Finding the right filter or size part is easy using our search function to help you find your filter or a compatible replacement air or water filter.

Find Your Filter Easily

Enter The Filter Part Number or Size from Your Current Filter in the Search, for example, enter LT700 or LG Water Filter. For an air filter, as an example, you could enter Lennox 16x25x5 or X6675. You can also search the brand links listed on this page to look at Brands and compatible replacement filters. Remember air filters are sold by Nominal Size which is a rounded size and filters with the same Nominal size may not be compatible. It is important to look at compatibility when choosing a replacement. To find out more about finding the right filter check out this article on filter sizing.
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.

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