This research investigates the problem of area exploration using groups of unmanned aerial vehicles (UAVs) under limited fuel constraints, where each group is assigned backup or search role depending on the situation. This paper presents an exhaustive approach in finding a way to explore the search area with the least energy consumption by discretizing the search length into intervals and designating points where a search group goes back to the base to refuel and the backup group continues the job the returning group was doing before returning. This approach guarantees that the search operation is not interrupted by this switch operation for refueling. Since the exhaustive approach takes exponential time, we propose a measure, for an allowed maximum execution time, to determine the way to search the area that costs the least energy consumption.