The best filter ever!

Thought this was a great price since I usually pay $35 For one. But these are not 4 like it says . They are 4.5 did not fit ! Now I have to return them.

I did buy this a few months ago because I like to have them on hand when needed. I buy this even though the guy who worked on my furnace and replaced the blower motor said not to use these filters. He said they were the cause of the blower motor going out, because they would have to work to hard and need replaced. But these filters, I believe, do what they are suppose to. I have dog's and these filters help me breath better when the air conditioner for summer or heater for winter.

I bought the 4" filters for the first time in the fall. It is worth the price difference. My unit is up in the attic so getting up in the attic is a pain. Now I only need to change the filter every 3 months and it really helps with the dust in the air.. The air quality in our home has really improved.

Excellent air filter. I buy these 20x20x1 sizes and tape them to a regular box fan for a quick, easy, and affordable air filtration unit that I can move around the house wherever/whenever I want. No need for any special high end unit that requires a unique filter that some company stops supporting.

I have been using Filtrete Filters since mid-'80s. I have upgraded with each introduction of an improved version and found they actually DO last 3 months. These filters keep out dust, dander and pollen. At present, I have 2 dogs & 1 cat in the house. My whole house smells fresh for 3 glorious months. They are not as cheap as Brand X, but very worth every penny; considering all they accomplish.

I have been using Filtrete filters to reduce the allergens in the air for the past 5 years. They have significantly reduced the particles in the air that had been causing my wife to have various allergic reactions, including coughing, watering and itching eyes and general difficulty breathing. I certainly will be continuing to use them from now on!

Outside, air quality was 300-1100 (off-the-scale and very hazardous) with smoke hanging in the air like dense fog. Inside, the indoor air quality monitor says the air is very clean (AQI 23). This is with running the furnace fan continuously and changing filters every 3-4 weeks. The only downside is the smart filter feature doesn't actually know when the filters are dirty, only how much air volume has gone through them.

Had problems breathing, eyes itched, migraines nonstop. Finally went to an ears, nose, throat specialist and was diagnosed with numerous severe allergies. Started on medication but it was not doing the full job. We saw these filters and decided to try them. What a difference! I could not believe how dirty the filter was. The first time we replaced it after the three months which is recommended. We changed it monthly for three months following that than every two months for the next 3 changes. Each month it became a bit less dirty. We could not be happier with the cleaner air!

I am happy with the performance of this filter. However although it slides into the box easily, it is hard to remove. It would be nice to have cutouts in the cardboard for finger holds. It is also hard to remove; it is almost as if it expands. I am afraid I will damage the wires in my furnace as I remove it. It comes out in a few pieces.