Here are several ways to find out the facing direction of a house.
Find out where the most Yang side of the house is (based on the Yin Yang Theory). The Yang side is usually the side that’s most “active”. Meaning, it’s the side where the road is and where most movement occurs. It’s also the side that can gather the most sunlight and Qi energy.
Using the above method should suffice. If not, you can use these other methods as cross reference.
Find out where the backyard is. As the name implies, the backyard should be situated at the back, or the “sitting” direction. The same concept applies for the front yard.
Check the house’s design and orientation. Which side is made to greet guests?
Imagine the house as a person. Which side would be the “face” of the house? Which side would be it’s back?
If your house is the standard conventional type, the above four steps should all produce the same result. If your house has a modern artistic design, then the facing direction can be tricky to find.
One method is to use the apartment door as the facing direction. After all, the front door is the mouth of the house that gathers Qi, isn’t it?
Another method is to use the facing of the entire building as the facing direction. The reasoning for this is that all units are under one roof, and they should all share a single facing direction based on the building.