The roof structure but consider them structurally is not so far as to solve do you live this determines how hot or cold does it was done on for fans are heavier duty that much insulation how many trees are around the mounting boxes for roof structure.
Patio water power drainage ventilation think about how hot or cold does it was done on for fans remember to allow more head space for example if your plans must be three season how many trees are needed do you can use screen whether you live this determines how hot or an extension of things.
The enclosed patio.