The term “stack-effect” goes back to the chimney. The heat source – in this scenario, the fire – heats up the air. Hot air rises and is discharged through the chimney, as it has a lower density than cold air. This effect can be used to replace air inside a house. For instance, when it’s colder outside the windows can be opened to let in cooler air. Warmer air inside the room will rise towards the ceiling, exiting via high openable windows, clerestory windows and skylights. Warm air inside is replaced by fresh and cooler outdoor air.
A clerestory is a usually a high wall with a band of narrow windows along the very top. The clerestory wall usually rises above adjoining roofs.
Originally, the word clerestory referred to the upper level of a church or cathedral. The Middle English word clerestorie means “clear story,” which describes how an entire story of height was cleared to illuminate large interiors.
If you want to maintain wall space AND keep a room well-lighted, or if normal solar access is either not possible or restricted consider this type of window arrangement for your home. Clerestory windows are most often used to naturally illuminate large spaces such as sports arenas, transportation terminals, and gymnasiums. But can be a great addition to any home.
If you are building an energy efficient home the stack-effect and the clerestory window can be a great helper to purge hot air out of the house. However, if you are building a house according to the passive house principles the stack-effect is not that important, since the ventilation system is taking care of the air-exchange and that your home stays cool. This means you can have fixed windows, which is a bit cheaper than having openable windows.