The sunny side generally points to the sunny side, and the room also refers to the room with the windows facing south as the sun room.
China is located in the northern hemisphere, so it is called the first house, facing south. At noon, the sun enters the room obliquely from the south, and the south is sunny.
In ancient Chinese, Shan Zhinan was Yang and the north of the water was Yang.
Extended data:
If you live in the southern hemisphere, the situation is just the opposite. The house will face south and the north will face the sun.
If you live near the equator, that is, between the Tropic of Cancer, the sun basically shines directly from the top of your head at noon, so there will be east-west convection in the windows of your house, because the north-south houses can hardly get sunlight.
The shady side refers to the north of the mountain and the south of the water.
Baidu encyclopedia-sunshine noodles