You may well ask, what is the best concept for roof ventilation. Let’s explain the meaning of concept:- A directly conceived object of thought Functioning of a new product or innovation. Of course, you obviously know this, or you wouldn’t have typed in the word concept. Well, let us start with what is not a good concept for roof ventilation, as follows: - Whirlybirds Don’t Work! See scientific evidence on this site – Case Studies…