Question

Ventilators provided at high height and window at low height

Answer 1

window is used as source of cold air because cold air is weigher than than the hot air so the window is on low height can let cold air through it and hot air is less heavier so it goes up and ventilator are on height it let go the hot air out of our house

Answer 2

Ventilators are made for the removal of hot air from room and the windows are made for the supply of cool air. Since hot air rises up and cool air goes down,ventilators are made at a relatively higher height than the windows.