As a general rule, if the WooWoo GT or GT LUX is installed within a dwelling (ie the walls etc are reasonably air-tight), then we’d always recommend the electric fan over the wind fan for total odour removal – just in case you have a prolonged period of low or no wind. If the WooWoo GT or GT LUX is installed in a ‘shed’ or similar stand-alone building, then the wind-powered vent should be sufficient.
The ventilation pipe and fan is just one aspect of the odour control system in the WooWoo GT and GT LUX. The advantage of the wind-powered fan is that the toilet can be completely off-grid, requiring no electricity, water or sewage connections.