Each facing and each sector has its own flying stars, their production and suppression 生克, for example, they can produce in, suppress in, they can produce out and suppress out and so on which bring different luck. Main door facing is not necessary the same as main door location. For example, main door faces South, it does not necessary mean door must be located at the South sector. The main door can be located at any of the 9 sectors.
For example, take a period 7 house facing S2 South 172.6°-187.5° Kan house 坎宅 ZiWu 子午as shown below.
When the main door located at South East (4, 6, 1) or at West (1, 9, 4) it will benefit academic excellent and favor academic related jobs like writing, teaching and research. Between the two, West is more beneficial and more wealth inviting.
When the main door located at South (8, 2, 6) it benefits your wealth accumulation. When the main door at South West (6, 4, 8) it still benefit wealth but spending will be higher.