Are you living in an apartment or independent house?
Vastu as a science tell you, how to live in a harmony with the nature. As a science, it extracts the positive energy from the natural elements of the universe - the panchbhootas, namely, earth, water, air, sun and sky. It all these five elements, for creating a congenial setting or a place to live or work in, in most the scientific way, exploiting the benefits bestowed by the five basic elements.
So, if your door open in an another area, which is closed porch of an apartment, could have have a different impact, as there is no direct sunlight coming in this area.
In my opinion, just the entrance in some direction will not have a very big impact but how do you place other areas in your home will have more impact like, kitchen, bedroom, bathroom, living area etc.
Please provide more information about your house.