Rating is not based on scientific analysis but based on observation and long-term use. The 1600 MPR appears to substantially reduce as claimed pollen, pet dander, smoke, bacteria and viruses. The latter two elements cannot really be determined. Changed every 2-3 months and the amount of collected debris in the filter is supported of filtering.

These filters work very well & keep my house & vents very clean! No allergies either & priced a bit high but lower than at other places. I date them & change every 3 months. Once I vacuum cleaned them to reuse once and they held very well for over 6 months!

This is a really great deal for filters that need to be changed every 30 days. It gets so expensive when you have to buy them one at a time so I was really happy to find a four pack! They have all sorts of sizes and honestly, you can buy three of them and get by for a whole year!

I have used Filtrete filters for years and they are consistently effective in pulling pollutants out of my home leaving it much more fresh. With droughts and dust a real problem this year the allergy causing agents are plentiful and everyone needs to use the higher grade filters for easier breathing!

I have tried cheaper brands but I always come back to filtrete. They have different merv ratings for different situations. I have Saint Bernards and lots of dog hair and dander and it takes care of it all.yes they are expensive but worth every penny.

The Filtrete Ultra Allergen Bacteria and Virus filter seems to be helping reduce my allergies, especially when used in combination with room air purifiers. The MERV rating of 12 is higher than I usually prefer since it can restrict airflow, but these filters make it worth having my A/C work harder throughout the day. They offer great value when purchased in a pack of four, and Filtrete is a leading brand in air filters.

I have used these filters for several years and don't have to change them out as often as other brands. Although it states they last 3 mos, I usually swtich them around 2 mos in summer. I don't have much along allergys so I can't speak to it's effectiveness or maybe that's why I don't have allergys :-)

My friend recommended these filters and I'm very happy using them. The air is a lot cleaner; I don't have to change the filter out for 3 months. I highly recommend, although pricey, it is definitely worth the money. Also, they have a reminder when to change out filters.

I always buy 3M filters. They feel like they work the best and are well worth the extra money than the plain-jane filters. Not only do we live on a gravel road in the country, we have 2 dogs that are inside/outside and shed. I also have some allergies, These filters help tremendously!

I only buy Filtrete, they're the best. Unfortunately my 10 year old furnace died 2 days after I received these filters and I never had a chance to use them. Replacement furnace uses a different size and the company I used provides free filters for 2 years so I will be returning these. Will buy the new size from Sam's when the free filters run out or if I decide the free filters aren't doing the job.