Question

why are ventilators in houses provided at the top of the walls

Answer 1

to accomodate air insie

Answer 2

Answer:

A house having windows but no ventilators should not be bought. This is because warm air is lighter than cold air and therefore, it goes up. This warm air can go outside the house mostly through ventilators. If there are no ventilators, then the warm air cannot go outside easily.