Free Shipping - Most Items Ship in 24 hrs M-F

Humidifier Filters

Lennox X2661 Healthy Climate #35 Replacement Humidifier Pad

I am a contractor please send me pricing on this item. 

  • OEM Lennox Healthy Climate #35 Water Panel Evaporator - # X2661
  • Size: 10 x 13 x 1-1/2
  • For optimum performance, replace panel once every 6 months or more often in hard water areas
  • Fits the following humidifier models:
    • Lennox Healthy Climate: HCWB3-17, HCWB3-17A, HCWP3-18, HCWP3-18A, HCWB2-17, HCWB2-17A, HCWP2-18, HCWP2-18A, WB2-17, WB2-17A, WP2-18, WP2-18A
    • Aprilaire: 350, 360, 560, 560A, 568, 600, 700, 760, 760A, 768 

Lennox Healthy Climate #35 Humidifier Replacement Panel, your whole-house humidifier, the Water Panel (also known as humidifier filter, water pad, evaporator pad), should be changed at least once per heating season. The pad is constructed of an expanded aluminum honeycomb mesh that is dipped in a clay coating. This coating is able to absorb and hold water. Warm, dry air is forced through the wet pad to introduce water vapor into the home. Factory original part Honeycomb filtration to trap mineral pollutants found in water and help prevent them from entering your home. 

Customer Reviews

Based on 15 reviews
Previous Review is wrong

I thought I Was reviewing something else. The one thing you should know about these panels is there is a "right way" to install them - so that the water runs "inward" when it goes down - not outward... painted mark UP


fits perfectly great price quick delivery


Great product and price.


I was very pleased with the timing of my order. Unfortunately I ordered the wrong size. But Atomic filters have made the return process very easy.

Great buy

Great product fast shipping good price.

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