I have one of these units in my home and am very happy with its performance. Actually, its performance improves as it gets used more and more! It reaches about 99% filtration as it nears its replacement period. That's right, instead of getting worse as it gets used, it gets better. And the other nice thing is that unlike common 1" paper or fiberglass filters that require replacement up to once a month, the AprilAire unit is good for 1 to 2 entire years before needing replacement.
So given the popularity of this filter, I thought I'd show you how to install it since it's a little tricky. But once you know the secret, it's a snap, and a breath of fresh air!