Bests & Worsts Reviews from Amazon

I clean air ducts with the job I have so I am a firm believer in a good quality air filter that doesn't restrict air flow that can cause other issues in its self. Merv 11 is a pretty good for not restricting air flow. The first thing I did was hold this filter up with a light/lamp about 5 feet away I could see light but not make any thing out on the other side of the filter which normally means it has a good density. The filter reminds me of the car air filters that k&n makes but maybe not at thick heavy or dark color. The frame is made of plastic and seems ok made but I would not drop it, it looks like it could crack or break. I was using the cheaper 3m filters which I was not impressed with. When I swapped out to the new air filter I stuck my hand in front of the vent while the air was blowing before and after the swap I did not notice and noticeable difference in air flow with my hand. Now for the bad and or negative. First it is made in China I would have preferred for this to be made in US. Second is the size I ordered a 20x20 I read some other reviews and some people said it was to small. I actually measured the size before I installed, the size is 19 1/2 x 19 1/2. Now I went on k&n website and it states that the are smaller because each frame manufacturer is slightly different in size this is true to a point there is normally not a 1/2 difference is size from frame to frame. The third thing is my air return is in the ceiling and every time the air turns on it picks the filter up and makes a slap sound and it makes a slap sound when it falls back down, this may not be an issues if yours is in the wall or floor. I am going to get some 1/2 on sided foam that is normal used to seal around doors and windows that should help prevent the moving up and down. I feel like the should have provided either some foam to make up the difference and they could have made some plastic pieces that could adjust to make up the difference. Also they recommend cleaning at least every 3 months. I will have to say I always recommend every 30 days in the spring and fall you maybe able to go two months if it's not to hot or to cold. There is also a lot of other variables that come into play. All and all it seems like decent filter, for the price it is one of the better washable filters I have seen. The other filters I was using where around $30 for 6 so I changed my monthly so I will save money in a year. Also when you wash the filter make sure it is completely dry before you reinstall it, I recommend buying a decent cheap throw away filter and install that for 24 hours to make sure the other one is completely dry then swap them back out.