Back doors are rather essential in feng shui—they let energy circulate. Houses or apartments without a back door run the risk of having energy stagnate in the home. They benefit from a yang decorating style—sparse, yet good, design. Windows that can open make a huge difference in circulating energy in homes that don’t have a back door (or side door).
The most essential point to remember about back entrances is: Don’t use your back door as your front door—your main entrance door. When you arrive home, come in through your official front door. For many people, that’s not a choice at all—there’s one, and only one, entrance door. But in free-standing homes, there’s usually a back door. And in many of those homes, the back door (or side door) is designed to be the entrance door of those who live there. Pity that! If that’s your situation, try to use your official front door more than 50% of the time. If no can do, at least make your main entrance door charming—and at the same time keep the official front door area stunning.
There’s a big difference between those two words: stunning and charming. The more charming your side door becomes, the more stunning your official front must become. A side door (or back door) must never compete (in visual appeal) with the front door.
It’s not so bad a situation when the official front door and the main entrance door are in the same orientation. (And it’s good if the main entrance door is in the garage or carport and is not very visible when approaching the home.) Then you still have one powerful bagua map that can be applied to the home. But if the main entrance door is on a side wall or (heaven forbid) the back wall of the house, you are likely to have bit of a tough time applying the bagua map correctly. You might consider only applying the bagua map to individual rooms of the home—rooms that have only one entrance door (such as most bedrooms).
Back doors that are in a direct line with the front door (and are in your direct view when you enter the home) let energy out too quickly. The easiest fix for most people is to hang a crystal from the ceiling, between the two doors, and say out loud, “The purpose of this crystal is to keep energy in the home.” (Crystals always represent dispersing energy in feng shui, so the energy from the front door is being symbolically dispersed into the home, rather than zipping right out the back door.)