Competition has a direct impact on the growth of the economy. Manufacturing systems can be improved by a well-thought-out production strategy. Problems with aggregate production planning and sales forecasting are leading an Installation Elevator Company to be unable to deliver items on time and have an impact on customer satisfaction. Studying and comparing forecasting methodologies used by installation businesses, as well as studying aggregate production scheduling in order to analyze and identify the lowest aggregate production costs, were among the goals of this study Aggregate production planning (APP) addresses two critical issues, labor level and inventory utilization, so that the variable needs from downstream processes may be met in a cost-effective manner with the work breakdown structure of all projects and their building strategies. To satisfy the changing needs of aggregate products, aggregate production planning is a planning and control procedure for all production processes. Determine production and inventory levels so that a limited labor and equipment can reduce total production costs on the other side, the goal of maintenance planning is to increase equipment efficiency in order to meet production demands.