hi
what you need to remember with any fan is the ducting, air will travel along the edge walls of the ducting the smoother the better.
when the fan pushes the air through the ducting any ridge or obstruction will create system pressure, air being pushed through ducting tends to roll along the edges if it hits an obstruction it will roll back on itself meaning the fan will have to work harder to overcome the system pressure until a point it just does not work.
with flexible ducting you must stretch it out as much as you can otherwise as above the ridges will make system pressure. if you can use rigid ducting & if required cover in insulation. bigger the fan the more system pressure it will handle.
what you need to remember with any fan is the ducting, air will travel along the edge walls of the ducting the smoother the better.
when the fan pushes the air through the ducting any ridge or obstruction will create system pressure, air being pushed through ducting tends to roll along the edges if it hits an obstruction it will roll back on itself meaning the fan will have to work harder to overcome the system pressure until a point it just does not work.
with flexible ducting you must stretch it out as much as you can otherwise as above the ridges will make system pressure. if you can use rigid ducting & if required cover in insulation. bigger the fan the more system pressure it will handle.