The effects of an entrance are always very powerful whether positive or negative. Crucially, the entrance of a building is the point at which the Space enclosed by the building communicates with the Universe.
The Space of every building is only a part of the vast Space of the Universe. But these two represent different levels of consciousness. The Space outside a building refers to the conscious mind, and the Space inside the building refers to the sub-conscious mind. Through the entrance to one's Space i.e. building, one moves from one level of consciousness to another - that is, the main door represents the shift from the conscious to the sub-conscious level.
Naturally the location of the main entrance of a building is of prime importance.
For analysing the effects, you should understand how to identify the entrance location on the plan. According to GuruVastu, by dividing the 360° around the centre of a given Space into 32 equal 'Angular divisions' - each measuring 11.25°, you get 32 possible locations of entrance to the built-up Space. This is the path-breaking approach of GuruVastu, which places it above all other methods being used in the name of
Once you have calculated the Entrance Locations as per GuruVastu, only then, you can match the symptoms of the building with the corresponding effects. Symptoms of the building refer to the adverse or beneficial situations being faced by the inhabitants like: abundance of money; career-success; not receiving payments on time; frequent accidents and mishaps; miscarriages etc.
Once the symptoms are found to be a 100% match with those mentioned in GuruVastu, then by using different techniques of GuruVastu, which basically involve GuruVastu's Theory of Five Elements, (normally, in the form of colours, or/and metals) the negative effects of that entrance can be nullified.