Re: Fellowes AP300 HEPA filter for Winix Size 21 Replacement

A Reader writes:

Dear Ed,

Thanks for all the information on your site.

Especially since I was looking at Electrolux, Winix, and Fellowes models, and then reading your reviews, finding out they were all made by the same company.

I was wondering whether I would be able to use the replacement HEPA filter of the Fellowes 300 model on the Winix 5300 model?

I ask this because, from searching around, it looks like Winix only sells their HEPA filter in a pack with 4 carbon filters.

Aside from reading your issues with their carbon pre-filters, I also figure I would probably end up buying after-market ‘cut-to-fit’ carbon filter sheets anyway to save money.

So I wouldn’t want to buy their HEPA filter w/ the carbon filter pack.

And I do notice Fellowes sells their HEPA filter for the 300 model by itself for half the price of Winix’s filter pack.

So from reviewing those models, does it look like Fellowes’ HEPA filter would work in the Winix 5300?

And really, is there actually any difference between the two HEPA filters?

Thanks alot,

A Reader.

Ed’s Reply

Hey Reader;

Fellowes HEPA, part number 9370101, is exactly the same as Winix size 21 HEPA, part number 115115.

I recently ordered the Fellowes filter and installed it in my Winix 5300.

The Fellowes version cannot be distinguished from the Winix HEPA.

The photo, while not as clear as I would have liked, shows the new filter installed and the dirty old filter.

The box says “Made in Korea.”

I don’t know if Winix or a third party manufactures the filters.

After inserting the new filter, I applied scotch tape to seal the edges, even though there was no visible gap.

Additional prefilters (not the Winix type), were a sheet of fiberglass window screen, two thicknesses of polyurethane foam, and a carbon-impregnated filter layer.

Measuring the new filter’s performance with my Dylos DC1100 particle counter, I was surprised to find near zero .5 micron particulate emissions, very good performance for a “value” brand air cleaner.

Larger 2.5 micron readings were zeros repeatedly.

The Winix HEPA with four carbon odor filters, lists for $80, and gets $70 at online vendors.

I conclude that Winix owners can use the “Fellowes” HEPA, around $30, and save money.

Winix size 21 HEPA filters fit the 5300, 5500, 9500, 9000, 5000 and 6300.

Best wishes,

Ed