The bottom of Primo has limited airflow area.
Total airflow area of intake through Primo base to bottom fans is 91.35sq cm.. a single 120mm fan has 101sq cm airflow area.. and that's not taking into account the lost of airflow area caused by the grill mesh of another 60-70% (grill mesh is 30-40% open area).

  • Left side has no airflow.. The grills on filters are totally cosmetic!! There's a solid surface behind them visible when you take them out to clean!!

    • . 0.0sq cm = Left side vents are fake
    • 16.2sq cm = Right side has 36x 3x15mm slots
    • 36.75sq cm = Back is 147x25mm
    • 15sq cm = Front has 5x 10x30mm
    • 23.4sq cm = Base is 2mm off floor with 126.5cm - 19.5cm for feet = 117cm + back area
    • 91.35sq cm = Total area
This does not take into account the area loss to grill mesh or turbulence (approx. 30-40% airflow restriction)..

33mm space between floor and bottom of case adds >420sq cm. That is with 30mm castor area deducted.
40mm space between floor and bottom of case adds >514.4sq cm of airflow area. This is with 6x 40mm block area deducted.

By comparison, a 120mm fan has about 100sq cm of airflow area and a 140mm fan has about 140sq cm of airflow area. It varies some because of center hub size differences.

Caster base for Enthoo Primo

30mm casUsing 30mm castors on threaded studs screwed into 7 ply voidless 10mm Baltic birch base (9mm actual thickness), holes drilled and tapped we have a total of 40-42mm increase in sysem height from floor, Enthoo Primo height goes from stock 650mm to 692mm tall.