Box Fan Air Purifier Filter for Cleaner Air and a Cooling Breeze Washable, Reusable, Compatible with Mainstays Box Fan Model FB50-16HB Frame & Filter size 20.5” x 20.5” Made in the USA

The challenge is to have clean air in a space that is:- 1800 sq feet- home to 2 humans and a cat- 50 yrs old, with dust from age & the continual repairs now necessary- using several expensive HEPA filter devices, with more improvement neededI purchased this filter 6 months ago. The first test is done! Question: does it capture more than a filter added to a box fan is already capturing? Answer: YES!- as shown in the photos, over time the outer filter accumulated significant dust - the grid pattern is made by the dust & particulates- also shown in the photo, this washable filter captured additional particulates that the first filter allowed to get through (in time)- the box fan was run at various speeds (it just has 3), continuously for 3 months.Is it easy to wash? Answer: YES!- It released the dirt very easily- I was able to thoroughly hand-wash it in soapy water in the sink, and rinse & hang in the shower, in about 3 minutes.Does it replace a carbon filter? Answer: NO.- Activated carbon has cleaning properties that this filter, or plain HEPA filters, do not have, such as capturing volatile organic compounds (VOCs).- VOCs are both biological (think gym shoes) and also released by paints, plasticized things like laminate floors, vinyl tiles and storage bins, etc. If you can smell it, it is a VOC.- filtering BOTH solid matter and VOCs are important for health. Some VOCs are hazardous, all solid matter is hazardous for lungs.Other thoughts:- It would make a HEPA filter last longer, yet it needs the structure of the fan and won't work with a cardboard frame.- It may work to mount this to a HEPA filter if it has a metal frame. I don't know if those are still made.- If you are interested in combining with HEPA, then you could put the HEPA on the opposite side of the fan.- As others noted, it is a tight fit to the fan, and caution must be used when removing it to keep the Velcro tabs on your fan- The tabs WILL stay, though, if you began with a clean fan, and also hold the Velcro tabs down as you remove this filter.- I suggest using a NEW fan, so there is no dirt to begin with, and cleaning the area for the Velcro with rubbing alcohol.- if the Velcro tabs still do not hold, they are replaceable from any craft / fabric store or notions department.I AM impressed! At the time that I bought this, I thought it might replace the fan-sized HEPA filters and save some money. It has done that.I hope that in the future, these might be made with the ability to insert a carbon filter right in between layers. That'd be much more attractive than my lashing of an additional filtert! In the meantime, I am happy with this configuration. It costs less, and by placing the carbon filter first I do not have to wash this one too terribly often. I can deal with this once every 6 months! Please note that in this home I am running 8 such fans in addition to using the the built-in furnace filtration, bathroom vents and oven hood. The house is also aired out frequently, and yet we still had this room to improve air quality. I expect to be starting a collection of these filters, now. I do wish that it fit on the fan a little easier, on the other hand, if air is allowed to escape a filter, then it will, so we may all need to be careful what we wish for. :D A smidgeon larger would be helpful.I hope that this review is helpful to you. It would be great if you let me know!

I wasn’t sure this would work for my sons room but after having it in the window for the be night I was APPALLED to see how well it worked at trapping pollen!! Even running it regularly out of the window it works wonders filtering dust in the air. I should have used this all along instead of wasting tons of money on air purifiers when my son was little. I’m a lifer now!!UPDATE:I’ve now run this product almost all summer with the windows closed and our AC on. Because we live in an old farmhouse, in the country, and by a state road the air is always dusty. Well... THIS THING IS AMAZING. Not only does it allow good airflow but it traps all the dust and crap, including cat dander and dog hair. I honestly have no idea why anyone would waste their money on expensive air purifiers when this is totally all you need!

Fits the fan perfectly. Lasko20 in. Power Plus Box Fan I got at home depot. The challenge with this filter is it is not as fine as a pleated furnance filter. Thus, if you want better filtration then you will need to go the furnance filter route. Either by the product that supports use of furnance filter or duct tape a 20x20 one onto the back of fan. Just realize the more you use you have to replace those at a added cost and probably harder on fan motor to pull the air threw as it clogs up.

The Fan Buddy 20" premium box fan filter does a great job in purifying the room air. I find it to be more effective than my expensive room ionizer purifier. Many reviewers have stated that their Fan Buddy does not accurately fit their box fan. This Fan Buddy that I purchased from Amazon perfectly fits my Lasko model 3723 box fan which is a terrific fan that I had also purchased from Amazon. So if you are looking for a cost effective way of purifying the air in a room then I strongly suggest getting the Fan Buddy 20'' premium box fan filter (not the standard box filter) and also getting the the Lasko model 3723 box fan.

I have PollenTec filters for my tower fans and love them, but what they have for box fans do not have the best fit. First it is very hard to attach the velcro strip around the curved corners of the fan, as hard as I tried for a smooth transition it puckered badly. Plus I had to cut out small v shaped sections where the screws attach the back grill. I want to be able to remove and clean as necessary The filter itself is made to fit multiple models of box fans, but for my Lasko B20200 it is a bit bigger than the rear grill so the fit is not as tight as expected. The positives are that I know it will do a great job of filtering out dust etc. It will be easy to clean and does not restrict the airflow appreciably. I was also not thrilled that the filter cost almost 3 times the cost of my fan itself. I am satisfied, but will not be buying another for my other box fan.

Sorry to say, it does not let the air go through my box fan like I expected. But it does give me privacy from the people that pass by my windows on the first floor. Have to maintain the fan at level 3 speed when I use the filter, to get the same air flow when I used it at level 1 w/o the filter. I guess the trade off is more electricity usage and more privacy w/ the filter.