In Vastu they have not mentioned a particular deity's idol that is to be placed outside. But the most common would be Lord Ganesh's idol. Ganesha is the God of prosperity, good luck and success.
Devotees of Lord Ganesha usually place his idol at homes. But most people are not aware the places where to keep Ganesha's idol so that it can bring happiness and success.
If you want to attract more wealth, happiness and prosperity, bring home statute of white Ganesha. Even pasting a picture can also work wonder for you. Place the idol of Ganesha in a way that the back of the deity faces the outside your house.
However, the best place to place idol is in the northeast corner of the house which is also the best location to setup the pooja room. If north east corner is not available then place an idol in a way that you face north or east while offering prayers.
