luxair extractors - when to change shape, if at all.

[ash_scotland88]

Looking to order a caporra ceiling hood, the exhaust is rectangle from the motor.

I am presuming it's easier to core through the house with a circle it'll be neater etc etc, even with builders employed than trying to form a rectangle shape in brick/brick.

 

With that in mind when should the shape change to circle? From the motor, before the exhaust? Not at all and tell the builders to get on with it...

[Nickfromwales]

There's plenty or rectangular > round adaptors for domestic ventilation, so I'd be more focussed on what external grilles tickle your fancy and then work the problem back from there.

 

If your builders can't stitch-drill a near perfect rectangle then you've got the wrong guys afaic.