If your system is installed with a filter box (a place to put a filter right at the unit), this takes the place of the filters that go in your regular return grilles. One of the benefits is that instead of changing multiple filters you can just change one. However, the reason you have filters in your return boxes at all is that they are usually much more accessible than your unit. We have seen some cases where homeowners completely forget about the filter boxes and a filter isn’t changed for an extended period (terrible for your unit). If your duct or return is undersized, installing a filter box right at the unit can reduce your return static pressure which can improve system performance and life.
What is the benefit of additional filters if my house already has filters?
If your system is installed with a filter box (a place to put a filter right at the unit), this takes the place of the filters that go in your regular return grilles. One of the benefits is that instead of changing multiple filters you can just change one. However, the reason you have filters in your return boxes at all is that they are usually much more accessible than your unit. We have seen some cases where homeowners completely forget about the filter boxes and a filter isn’t changed for an extended period (terrible for your unit). If your duct or return is undersized, installing a filter box right at the unit can reduce your return static pressure which can improve system performance and life.