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.
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.
Was skeptical at first. Turned out to be a great decision. Had a custom filter made for a funny size return vent. They showed up a week later with the EXACT dimensions I provided. Now I order all my filters through them on auto renewal.
You can get furnace filters at a big box store cheaper, but you will not get the same quality as you do with these filters. One look and you will know that you are getting what you paid for. Very well made. You can't put a cost on clean air for your family.