Don't really know yet. It took so long to get it that I just installed it a little over a week ago so haven't had a chance to see how good it is. And I also received a 2nd one, one that was supposed to come in 3 months. Hope they don't keep sending them in that haphazard way.
I am well pleased with my filters. We had to install a new ac/heat unit in Aug of last year and was so glad to be able to locate a source for our new filters. Thank you for your fast and accurate service. MM
We haven't had them long but the air quality has improved dramatically. We have to keep things closed up because it is so cold outside. The air in the house does not smell closed up or stale. Very pleased.