| Honeywell HRF-D1 filter replaces Honeywell HEPA filters 20500, 20590, and HRF-11.
The filters require stacking of two units for some models.
-Replace Honeywell 20500 (for air purifier series 10500, 17000, 17005) with two HRF-D1.
-Replace Honeywell 20590 (for air purifier series 10590, 50100) with one HRF-D1.
-Replace HRF-11 with an equal number of HRF-D1
Each Honeywell HRF-D1 includes 1 filter and 1 gasket. Replace filter every 1 to 5 years. We recommend annual replacement.