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Community and Q&A

Attic Filter for Ducted Mini

ATXMatt | Posted in General Questions on

Installing a ducted mini split in my small barndo apartment. Our Man J recommends two air returns (master Bed and Livingroom). 

I am looking for ideas for an at unit air filter. Do I use a standard 20×20 5″ filter housing, but then neck it back down to the 30×7 return side of our handler? 

If no at unit filter option, do I just use standard 2″ filter returns at both returns and swap the filters at the same time? Aprilaire 2025FG13 or so.

Lastly, is there such as thing as too much return?

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  1. Deleted | | #1


  2. Expert Member
    Akos | | #2

    The easiest is a return air boot with a standard filter box. Something like a 24x8 boot can be adapted to match up to the ducted unit then install a 25x16x4 filter frame. Best is always to stick to standard filter sizes, much cheaper and easier in the long run. The problem with this in ceiling install is that takes up a lot of space and you need lot of room on the side to get the filter out.

    The simpler is to go with a filter grill, installed either under the unit or to the bottom of a length of 24x8 duct behind the unit. Use a 2dn filter grill for your bedroom return.

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