Student or Learner
They are fans, which provide ventilation. (They hardly seem necessary.)
These are common in Pakistani houses. If there are no fans but those "holes" and a window or something else like that to cross the air. What would you call it?
I do not know what "cross the air" means. I also don't know what you are referring to. That huge hole in the wall?
Last edited by Tarheel; 10-Jan-2015 at 20:42. Reason: spelling
Having a couple of windows open provides a "through draft" or a "cross draft" but since there doesn't appear to be any glass in the main "windowframe", I can't see why those 4 ventilator fans would be needed.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.
For better efficiency, ventilator fans are normally installed on the openings through the walls and not on the windows. Windows are not meant for that purpose, they are meant for natural ventilation. The proper placement of windows on the opposite walls of a room allows for through/cross ventilation which is desirable for buildings in warm climates.
not a teacher
The position or height of mechanical fans or ventilators is immaterial as they work on the principle of suction. The fans turn to draw air out of a room creating a negative pressure which causes fresh air to move in through other openings.
The positions matter only with wind-induced ventilators which rely on the natural, upward movement of warm air (air current or draught) where the openings and ventilators are preferred to be located at the highest levels.
not a teacher
They look like clumsily fitted air-con to me.