I have not used them yet . This will be the first time using them.I still have the standard ones. The only thing I look at is the color of the filter when I take it out.
it is great to order several months at a time so I have them when it is time to change them. air is always more clean when filters are changed regularly.
The filters that i received are a good quality as well as i feel that the air is being filtered breedability and the sizes have matched what i require for my home
i bought these before & loved them. this time the 1st out of the 4pack . created so much flow resistance that it made an awfully loud noise and was so much reduced airflow that the filters bent und the pressure