Bests & Worsts Reviews from Amazon

I purchased these filters instead of the Filtrete Micro Allergen Defense filters I had been buying previously since the 3M filters have gotten way too expensive. Overall, these filters are better in many ways than the 3M filters but fall short in one respect. Pros: the Aerostar filters are better supported than the 3M filters (see photos), heavier (8 oz. vs. 7 oz. for the 3M), and have more pleats. The generally feel more substantial and rigid than the 3M filters. Cons: they are smaller than the 3M filters and may fit more loosely depending on your ductwork. These filters are 19.5 x 19.5 x 0.75 inches while the 3M filters are 19.7 x 19.7 x 0.75. I used foam tape along the edges of my return ducts to make it a tight fit. Considering the price difference and the overall better quality of the Aerostar filters, I will certainly buy them again. Photos: 3M filter is on the left (somewhat dirty since I was replacing them), Aerostar filter is on the right.