Fan-Box, wood, 4250 m3/h, 2 in-holes, each Ø app. 24 cm

The isolation of foamed plastic relevantly helps to reach such a low level of noise in this fan-box. The same is used in sound studios and cocert halls and its special shaped surface kind of swallows the sounds the snail-shell fan makes while working. Although the snail-shell fan itself is very quiet due to it's construction.
The layer of isolating foamed plastic can not minimize the high effort and capacity of the fan. To utilise the high capacity fully, you can mount two air hoses going into the box, for there are two holes of 24 cm diameter each.

To install the fan-box right, you have to mount wall flanges to the in- and out-holes of the box. Only then you can fix the air hose to the holes.
The flanges should be wider than necessary for the holes. For a wider flange, you would need a wider exhaust hose, and the wider the hose - the lower will be the air drag inside it. A low air drag entails a low noise.

With a speed controller for your fan you can decrease energy consumption and controll the operation of the snail-shell fan.

The dimensions are:
Length x width x height = ca. 61,5 x 60 x 60 cm
out-hole: ca. 29,5 cm wide and ca. 28 cm high
2 in-holes are: each ca. 24 cm
power: 550 Watt
current: 6.0 amps