Bests & Worsts Reviews from Amazon

I purchased Aerostar MERV 13 filters in the 20x30x1, 14x30x1, and 12x12x1 sizes for my HVAC systems. As a point of comparison, I have always used 3M Filtrete filters in the red packaging. These either have a 1000 or 1085 MPR rating, which would be closer to a MERV 11 rating. Here are some things to note: - Each Aerostar filter was clearly labeled with respect to its nominal size, actual size, and MERV rating. No brand information is printed on the filters. - In all cases, the Aerostar filters have the same or more pleats than the 3M filters. Also, both the wire and paperboard framing for the Aerostar filters are more substantial than the 3M filters. Lastly, the Aerostar filter media just appears to be denser than that of the 3M filter, as it lets less light through. In theory, I'm expecting the Aerostar filters to perform best unless there is some more subtle difference in the filter media. - Irrespective of the actual dimensions printed, the Aerostar filters are always between 1 to 3mm smaller in each dimension compared to the 3M filters. - When installing the 3M filters, I have always found them slightly oversized such that I usually have to crush a filter's frame a bit to get it mounted. As a result, it is doubtful that any air can bypass the filter and the only way the filter moves is if I tug it firmly to remove. - When installing the Aerostar 20x30x1 filter, it remained snug to the vent frame and did not fall from the ceiling even with the HVAC fan off and grate open. If the filter was jiggled a little, it would fall though. In other words, it wasn't tight like a 3M filter. - When installing the Aerostar 12x12x1 filter, it did not stay snug to the vent frame. I had to slide it in and close the grate to keep it in place. Despite this, I haven't heard any filter movement when the fan turns on or off. - When installing the Aerostar 14x30x1 filter, it was similarly snug to a 3M filter. If a problem develops with any of the filters, I think I'll just use double sided tape to secure them as necessary. I am satisfied with this given how much I saved over buying 3M filters. - For reference, the actual dimensions printed on the 3M filters are 501mm x 755mm x 20mm, 349mm x 755mm x 20mm, and 298mm x 298mm x 20mm. In comparison, the actual dimensions printed on the Aerostar filters are 502mm x 756mm x 19mm, 352mm x 759mm x 19mm, and 298mm x 298mm x 19mm. Irrespective of the printed dimensions, the real world dimensions, as explained above, don't exactly match the specifications. - The 20x30x1, and 12x12x1 sizes were shipped directly from Amazon, while the 14x30x1 size was shipped from Air Filters Delivered. The filters shipped from Amazon were received in perfect condition as they were double boxed. The filters shipped from Air Filters Delivered were slightly battered and deformed.