There are cases where ceiling fans cannot be installed. If the ceiling height is too low, typically less than eight feet, it can be hazardous to install a fan. Additionally, if the ceiling structure cannot support the weight of the fan or lacks a proper electrical connection, installation may not be feasible. In some cases, building codes or regulations may prohibit the installation of ceiling fans in certain areas or structures. It is important to consult with a professional electrician to assess an installation in specific circumstances.