Can I open the window on the back wall of the lobby on the first floor? Will it affect Feng Shui?

Hello. Our information here shows that windows can be opened, but the older generation came to build the house and left no windows on the back wall. An old farmer said that there are three main reasons. The first one that comes to mind most easily is to protect our daily privacy. The second is safety. If there is a window on the back wall, it is very likely that a thief will enter the house through the window, which will seriously affect the property safety of the owner. The third is feng shui. If the back wall is also windowed, it will strengthen the air circulation in the house, and it is difficult to gather gas, which means it is difficult to keep money.