this post was submitted on 31 May 2025
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[–] anomnom@sh.itjust.works 9 points 5 days ago

Yup, and adding the cardboard shroud helps keep it from stucking unfiltered air into the flow.

I think the main reason for the 4 filters is to reduce load on the fan and increase filter life. But many forced air heating systems get by with one or two filters stacked on the inlet.