Energy enters the home from the facing direction. This direction is the side of the house that has the best unobstructed exposure. The facing direction is not necessarily the same as the entrance direction. Try not to get confused between the door direction and the facing direction as these can often be two separate things. 
A lot of houses have their front door on the same side as the facing, this can make things more obvious as it is then easy to see the so called “eyes” and “mouth” of the house. Some houses can have a certain facing direction while the frequently used entrance is found elsewhere. It can then sometimes be a difficult task to establish the facing direction on some buildings.

Take your time and view the building as a whole. You can imagine that the building is a person sitting and looking out. What side of the building is looking out? This is the facing direction.
If you live in a multi-storey apartment building, you must find the facing direction of the whole building, rather than just your individual apartment. The formulas used on the whole building are then scaled down to fit your apartment. This technique is known as small Tai Chi.

What if you can’t determine the facing direction? The original architect who designed the building would have always intended one side to be the front or the facing direction. Sometimes you have to take your time until you spot the facing. 
Once you have determined the facing direction, you can then use a compass to get the precise degree. Find the centre of the facing directions side then stand with your back to the building and face out with the compass. Note the degree on the compass.

The Chinese compass or Luo Pan is divided into 24 mountains or sectors. Each mountain is given a name e.g. Ding, Ren, etc. For a measurement taken with a western compass we can convert the degree to the corresponding 24 mountain for use with our Feng Shui formulas.
Another way to use a western compass is by dividing the compass into its 8 main directions: North, South, East, West, Northeast, Northwest, Southeast and Southwest. Each direction is then again divided into 3 more sectors each of 15 degrees, so you end up with North 1, North 2 & North 3 etc. This has divided the compass into the corresponding 24 sectors.