Filtrete 24x24x1 AC Furnace Air Filter, MERV 13, MPR 1900, Premium Allergen, Bacteria & Virus Filter, 3-Month Pleated 1-Inch Electrostatic Air Cleaning Filter, 6-Pack (Actual Size 23.81x23.81x0.78 in)

Was buying these for a while and decided to try a cheaper brand to save a few bucks; didn't realize how much the quality matters. Cheap brand immediate whistled and bowed due to lack of air flow and also made my bill go up with the extra system strain. Won't switch back again. These filter great (we have 2 high-shed dogs and several cats) and they have no trouble keeping up. They fit well and go in easily, and most importantly are completely *silent*

I have been using these filters for about a year in our house and needed to replace it and had to go to hardware store and bought a replacement but could tell a huge difference with dust. I have purchased these 4 times now and will continue to buy them. They are expensive but worth it.

These filters are superior by far. The dense pleating on this filter allow greater surface area across the filter. This provides far better air flow to far ends of the HVAC system. If your home suffers from lack of air flow, or you want improved air flow, go with this type of filter. You can measure relative air flow using a simple sheet of 8.5 x 11 inch paper over an upward facing outflow vent anywhere in your home. Hold two near corners and suspend it above the vent to see how high the airflow will support the paper. This one gives me a full 18 inches of paper lift at the extreme vent ends of my system. Other cheaper filters don't even come close to that, providing me only about 5 inches of lift at the extreme end of the system.

Perfect replacement air filter. I’ve got some asthma and a hairy dog in the house, having a high quality filter is necessary and this is everything I need in a replacement.

Incredible filtering ability. I will likely never buy another brand of filter unless the price on these are exorbitant.I use this filter as a pure filter to our Panasonic ERV (energy recovery ventilation) system.This is the best performing filter that I have tried in the last 7 years.Pictures show old filters and new filters. Far left is the filtrete filter after 3 months. The others are the HEPA and activated carbon filter that I replace every 9 months.

13.5" x 29.5". My HVAC filter holder in the ceiling is this size. I don't know why but it had to be an odd size for 95% of home a/c heat pump filters. 14" x 30" I literally have to jam in to get them in. Maybe it's because it's a Bosch, German system. I don't know. What I do know is that there are filters that are the right size, and I bought them. Big mistake, The ones that fit were generally more cheaply made. I went to remove one while the system was going and the filter was half sucked up into the intake, seriously! I have never had an issue with a Filtrete filter hold it's shape under load. The other thing with the cheaper ones is noise. With the Filtrete I don't get the baby wind tunnel sound when the system is running.

Super quality filters, the best I have found.What I noticed was that these filters have probably 4 or 5 times the number of pleats which has the effect of a much larger filter, thus less restriction of a similar filter with far less pleats.

Can't find in stores any more, glad to have these on poor AQ days, was leery of ordering online, but arrived unbent and in perfect condition. Have to change more often because filter catches smaller particles, but that is how it works.