[shadowbot]

Raptor from what I know about my parents' wind turbine the company that installed it did an evaluation based on the average of their electricity bills in the past few years. Thats how they found out what their energy needs would be. Then they did another wind evaluation based on the location of the home and how much wind it receives and at what height. Using that information they have some way of calculating the size and placement. Im not sure theres a simple formula to figure it out I think there might be way to many variables since location is such a huge factor in windiness and in amounts of electricity used.