Cooker hood ducting

As part of my kitchen refurbishment I have had a cooker hood fitted. Due to the constraints of the building design the fitter has arranged for the hood to extract to the outside via three metres of flexible ducting.

Being essentially a plastic covered spiral wire the internal surface is not smooth. Does anyone know what the effect will be on the efficiency of extraction? I'm wondering whether I should replace this flexible ducting with rigid smooth sided duct.

Stig

There will be no drop in performance, at worse water droplets may collect in hose but will evaporate, this same hose is used in Tumble dryers, do not worry

This is a standard installation, don't worry!!

Thanks for your responses. One less job to eat into my dwindling bank balance!