Very confusing thing to buy. Pretty easy on your site. A friend gave me the link and I'm very glad he did. The filters are so much better than the ones I have been buying.
I live in a complex that uses fiberglass filters. Right now we're going through many fires in the state I live in and therefore poor air quality. I think this filter is helping to keep some of it out ! Fingers crossed. It certainly seems like it will compared to the fiberglass supplied by the maintenance crew.
I bought them to filter out the smoke in the house from our California wild fires. The one I installed seems to do the job very well, and I was relieved when I installed it that a non-scientific check indicated no significant reduction in the force of the output from the home HVAC blower.
Filter were the perfect fit, great quality & size. I will be buying them again when I need them. The price was really good as well and I got them really fast.
Filters took awhile to arrive which isn't so bad, but when they did arrive I was disappointed to find that the hard paper grid that keeps the filter in place took up a very high percentage of surface area when compared to my old filter (see pic). I'm guessing this reduces the CFM which is not what the mechanical engineer who designed my house had in mind, but worse yet, it causes a lot more noise then my previous filter.