Aerostar 20x20x2 MERV 13 Air Filter, 6 Count, ACTUAL SIZE (19.50 x 19.50 x 1.75), HVAC, Air Conditioning & Furnace Filter for Allergies, Dust, Pet Dander & Smoke (MPR 1500 / FPR 10), Made in USA

I buy these pretty often and use them for a home air purifier. It's able to filter a huge amount of air in the home pretty effectively. It's wild how much these filters are able to catch, you can tell easily when swapping them out with the new filters. Great filters definitely worth it

Exactly as described. I used it to make a DIY air purifier. Came in a properly sized box so the filters weren't damaged.

Best filters I have found at a reasonable price to construct a home made box fan filter referred to as a Corsi-Rosenthal filter. Easy to make, couldn’t be easier to use, works extremely well.

I bought a 6-pack of these MERV13 20x20x2-inch filters to make a variation of the so-called "Corsi-Rosenthal" air-filtration device for my one-car garage, where I have a small woodshop. The air can be full of tiny particles that are not good to breathe in. Four filters are duct-taped into a box shape with a cardboard base and a 20-inch window-fan resting on top, pointing down into the box so the dust collects on the inside of the filters; the filters are oriented so air flows outward. The 2-inch thickness provides good air-flow. My only gripe is that they're fairly pricy and since I only needed four, for my purposes the 6-pack offers only acceptable value for money, not good value. But the home-made air-filtration device using these MERV13 filters delivers filtration performance comparable to an $800 piece of equipment, so in that sense, it's very good value for the money.

So I love these for making home made fan filters. The 2” thickness makes it sturdy and the 20x20 is the perfect size for box fans. The price is going up so that’s a bummer. But I take 4 of them and tape them together in a box formation and lay the box fan on top. The fan pulls air thru the filters and helps clean out the dander and dust from the house. After a couple months, It’s clearly evident how much it’s cleaning the air.

These work and fit as advertised, fast delivery.

These are half the price I would have paid at a box home improvement store...if the stores even bothered to stock them. I love these filters, I love how high I can get the MERV rating, and they are as good or better than a 3M one. At half the price. I am sold. Had wildfire smoke in my area, cycled through filters every few days, kept the air in the house clean and carcinogen-free. This is one I definitely hit the 'order again' button on.

These work very well in my Corsi-Rosenthal box.