AIRx 21x21x4.5RR-ALLERGY | Our#: 176987

21x21x4.5 AIRx ALLERGY Rheem/Ruud RXHF-E21AM10 Replacement Air Filter - MERV 11

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AIRx 21x21x4.5RR-ALLERGY | Our#: 176987

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Reduce common allergy symptoms

  • Reduces allergy irritating particles
  • Captures allergens like dust, mold spores, pet dander, dust mite debris and more
  • Lessens odors from car fumes & smog
  • Creates cleaner indoor air
  • Actual Dimensions: 20¾" x 20¾" x 4⅜"

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Product Details

21x21x4.5 AIRx ALLERGY Rheem/RuudRXHF-E21AM10 Replacement Air Filter - MERV 11 (actual dimensions 20-3/4" X 20-3/4" X 4-3/8") - Rated MERV 11

Replaces media filters used in Rheem / Ruud model RXHF-E21AM10 21" Air Handler Media Air Cleaner Cabinets.  Replaces Protech 540012, will also replace 540042, PD540042.

NOTE:  This filter is not manufacturered by Rheem or Ruud. 

These deep-pleated filters are manufactured to fit in Rheem and Ruud Media Exact Fit Air Cleaners. Expect comparable quality of construction at a value price!!  The OEM filters are typically rated at MERV 10 - but these filters are rated at MERV 11.


  • Moisture resistant frame remains sturdy even in high humidity
  • Rust resistant galvanized wire downstream gives the filter rigidity and holds media in place after installation  
  • Built-in support fingers hold pleats in place and allow for maximum dust holding  

Do you want to know about the technical specs?

Nominal Dimensions
21 x 21 x 4½"
Actual Dimensions
20¾ x 20¾ x 4⅜"
Filter Media
Electrostatically charged 100% synthetic gradient media that does not support microbiological growth
Filter Support Grid
30 gauge galvanized expanded metal grid
Moisture resistant double-wall beverage board
Max Temperature
180F (82C) continuous service, peak 225F (107C)
Max Humidity
Resistant to 100% R.H.

Replaces These Filters: