Review on 🍃 Honeywell Universal 14-inch Air Purifier Replacement HEPA Filter: HRF-F1 / Filter (F), White - Superior Air Cleaning Efficiency by Milagros Iser

I use these filters on the 50300 which requires 4 stacked filters. The instructions suggest spacers between these pleated filters. They are actually struts, about 3/4 inch thick foam. Spacers were not required on my model, so there was no loss of filter area. The models 12520, 17400 and 50200, on the other hand, each have 2 stackable filters and 2 dividers that take up about 1/2 of the filter volume. This means that the 11520 and 12520 have the same filter capacity, but the 12520 has 2 spacers. Another problem is the loss of filter area between (for my device, model 50310) 4 short filters and the original single filter. high filter. For each sheet filter there is a top and bottom part that takes up space for the filter. Honeywell didn't use flat filters, which take up much less space and apparently much less capacity. The filter instructions say that with light use I should get 3 to 5 years from my new stackable filters. The instructions for my new unit say I should replace the smaller flat HEPA filter every year.