The K&N cabin air filter is still a cotton gauze media. So bad. Normally I don't say anything as simple as that, but in terms of filtration, it is. Their refresher talks about making the media regain "electrostatic" properties. Umm, no, not how that works.
K&N unfortunately is one of those companies that made good products for motorcycles decades ago when technology wasn't very good, but is now left being mostly advertising garbage products, at the expense of other's hard earned money.
For a cabin air filter, charcoal is a great addition to a solid cellulose media. I use either a Bosch HEPA, Fram Fresh Breeze, Toyota charcoal filter, or Mann with the polyphenol layer. Which ever is the cheapest at the time, around $15.
The K&N and cleaner kit is $50 on amazon, so in about 3.5 years, the K&N breaks even. But when I was reading about the refresher, it says the kit will provide about 3-4 cleaning. So you are really not saving money till about 5 years in. Not worth it ever in my mind, having had cars that don't have cabin air filter to begin with, I sure love having one in my 200, and wouldn't want to save a couple dollars a year, and deal with cleaning filters, to have more pollen pass into my cabin.
My information and experience with the K&N Cabin Air Filter are different.
The filter media is variously described as "advanced synthetic filter media" (
K&N Washable Cabin Air Filter - Reusable Cabin Filters) or "Non-woven Synthetic" (
K&N VF2000 Cabin Air Filter, Replacement Filters), but in any event, it is not "a cotton gauze media" as you describe.
The Refresher Kit sold by K&N (
K&N 99-6000 Cabin Filter Cleaning Care Kit, Filter Cleaning Kits and Accessories) is nothing more than a mild detergent and air freshener spray. It is entirely up to the user whether they use the K&N kit or just use something like Simple Green diluted 1:1 and Fabreze spray - either choice yields the same results with the latter being much cheaper. Even if the K&N kit is used, it would be capable of many more than 3-4 cleanings.
Living in the high desert, and traveling extensively in Arizona, New Mexico, Nevada and Utah, dust mitigation is the most important performance factor for a cabin air filter in my use case.
The stock filter that came with my truck was worthless for stopping anything smaller than a leaf, it is single use with a replacement cost of about $14 depending where it is purchased (
2013 Toyota Land Cruiser Parts - Camelback Toyota Parts - Genuine OEM Parts - Free Shipping).
I've tried a couple different filters to see if I could find one that worked better:
Toyota 87139-50100 Charcoal Cabin Air Filter, single use MSRP $35.00, discount price $25.61 + shipping (
2013 Toyota Land Cruiser Parts - Camelback Toyota Parts - Genuine OEM Parts - Free Shipping):
MAHLE LAK 490 Charcoal Cabin Air Filter (dates on box should be 2016, not 2017 - I was getting ahead of myself), single use, online price $16.80 + shipping (
2013 TOYOTA LAND CRUISER 5.7L V8 Cabin Air Filter | RockAuto):
Both were better for dust mitigation than the stock filter, but both allowed the fine stuff to migrate downstream of the filter.
Then I tried the K&N VF2000 Cabin Air Filter, mutiple use, MSRP $63.29, discount online price $40.99 w/ Free Shipping (
K&N VF2000 Cabin Air Filter, Replacement Filters):
This filter outperforms all other filters I have tested. What sets this filter apart is the mating surface between the filter and the filter holder. On stock and other filters, the seal is dependent on cotton media or open cell foam - neither of which is airtight. On the K&N filter, the mating surfaces on all four sides is a rubbery, compressible material that yields an airtight seal:
And if that weren't enough, you get a really skizzy K&N sticker!
So, basically, my take is that for about $5 more than Toyota's premium replacement filter, with the K&N I get a reusable, better performing filter.
YMMV.
HTH