Choosing the orientation of a house is primarily about maximizing sunlight and airflow.
In colder weather, the Northeast monsoon often brings chilly winds, so it’s important to minimize drafts while maximizing sunlight. Conversely, during hot weather, winds typically come from the South (including Southeast and Southwest), making it ideal to allow these breezes into the home.
Based on this need, Vietnamese people commonly prefer to build their houses facing South, as Vietnam is located in the Northern Hemisphere. In winter, sunlight usually shines through South-facing windows, allowing the house to absorb heat from the sun and stay warm. In summer, the sun’s rays become more direct and no longer reach the South-facing windows, while the South winds can freely enter the house through the South-facing door.
Thus, having a house oriented towards the South ensures it remains cool during the summer and warm in the winter. However, this principle is only applicable to those living in the Northern Hemisphere; in the Southern Hemisphere, the opposite is true, and houses should be built facing North to achieve similar benefits.
