Is it permissible to consider the price of an air conditioner purchased for elderly parents as part of Zakat al-Mal (money)?

If the parents are in need of an air conditioning unit due to high temperatures, and providing the unit falls under their essential expenses which are obligatory upon the financially capable son, then it is not permissible for the son to give them Zakat (definition) to purchase the unit. However, if the son is unable to provide for their expenses, then it is permissible for him to give them Zakat, provided that he transfers ownership of the money to them, and they undertake the purchase themselves or appoint someone to do so.