External sideways extractor vent??

[Bettyonholiday]

Having a kitchen extension which is nearly finished. On the back wall we have an extractor fan from a cooker hood which points out into our garden. It has a cover on it so the air is vented downwards. Our neighbour wants it to point back across and towards our property which would mean we would need to put the vent on sideways. Our builder says this won’t work as rain / wind could get in. My question is do sideways extractor vent covers exist?
Its not a biggie but I dont want to upset my neighbour and would be grateful of any ideas. Thanks!

The position is all that matters not the angle of the cowl. Unless it's literally on the boundary, the direction that the vent looks like it's "pointing" won't really have any effect. As your builder mentions the apparent direction is merely a rain prevention measure. As soon as the warm air comes out it will be dispersed by the wind.
You mention that the real point is just to satisfy the neighbour so you could always put a screen or plant up, or get a round cowl and angle it slightly.

Many thanks johnd2! Yes I would like to sort it somehow as its gotten a little unpleasant (angry emails and letters!) - you mention a round cowl - where can you get those from? Many thanks

if they're whining, you can run the duct anwhere you want and put a vent on the end. If the neighbour thinks this will help, good luck to him.

extra length on the duct will increase resistance to airflow (there are ways of calculating it, the fan supplier may have the calculation)

I favour a cowl vent on the end because it sheds rain and wind, and doesn't rattle as much as most. 125mm or 150mm duct (preferably rigid) will give better and quieter airflow than 100m

cowl vents

more vents

Round cowl i just googled for 5 inch round cowl vent
www.airflow.com/Product-Detail_/pg_EMGR/9041226