Usability evaluation for applications based on emerging information technology brings new challenges. Grid Computing is a relatively new, distributed computing technology, based on sharing different types of computational resources, located in various geographic locations. Technical knowledge of grid users is expected to decrease in the future; that is why the usability of Grid Computing applications will become a main issue. There is a need for new usability evaluation methods or at least for the use of traditional evaluations in novel ways. A set of heuristics is proposed and validated, in order to help the heuristic evaluations of Grid Computing applications.