You cannot just put your air conditioner on the ground for a few reasons. First of all, animals can easily climb up to the air conditioner unit if it is placed on the ground that increase potential damage caused by animals. As they might eat or build nest on top of the unit, which small pieces of wood or stone might come along with them. If things get inside the unit will cause damage and it might be costly to repair. Secondly, rainstorm and snow melt in spring will lead to water pooling on the ground so that it is not safe to place the air conditioner unit on the ground area. Thirdly, the ground might not be perfectly leveled. Placing the air conditioner to the uneven ground damage its electronic components and lead to operational problems. Furthermore, raising up the unit is easier for the inspectors to do the regular check up. Therefore, the best way to put an air conditioner unit is to raise up and place it against the wall. Wall bracket can support the air conditioner unit well as they can support 200-450 lbs when even loaded.