The Motor in a BBQ Rangehood needs to be of a quality that it can easily exhaust fumes,smoke grease.It is not enough to say that a BBQ Rangehood has 2000 -3000 m3/hr exhaust beause it is not the rate of exhaust that determines its ability to exhaust but rather the quality of the motor to be able to handle the exhaust rate required without slowing down & increasing in noise. In some cheap BBQ Rangehoods the motors will actually stop if they cannot cope.