HVAC Gurus

[Byron Trantham]

I have JDS air cleaner in my shop and it has a "horse hair" final filter. Which side is supposed for face the air flow, the rough side or the smooth side?

Thanks.

[Jim Finn]

I am not familiar with the filter you mentioned but air filters are made to have the air flow over the less dense surface first.

[Frank Hagan]

Rough side gets the air first. More surface area to trap dirt that way.