I have had one like this since 2007.
http://www.spar.com....anas-pared.html
I believe mine is a "prima".
never had the motor fail, it is vented to the outdoors, it works, and it looks good.
They dont sell them at Jumbo.
They cost more than the ones from the ferreterria.
There is a showroom down on the corner of Santa Fe and Cerrito.
But, sure, you can just hack a hole in the wall and put in a circular fan. I would recommend some kind of sheetmetal hood on the outside, then, so that rain, and vermin, dont get in. A screen would be good too. Palomas love to nest in just such a place.