This report presents a research proposal focused on improving the efficiency of pressurized boilers, specifically fire tube boilers, through the implementation of air preheating technology. The study aims to reduce fuel consumption and overall energy costs in large-scale steam production industries. The research involves installing air preheaters and collecting data to analyze the impact on boiler performance. The methodology includes assessing boiler efficiency using input-output methods and calculating the reduction in fuel usage and efficiency gains. The findings indicate that preheating air can significantly increase boiler efficiency, reduce fuel consumption, and lower operational costs. The report also emphasizes the importance of maintenance for preheaters to sustain energy savings. The analysis includes various charts and formulas to support the conclusions, providing a comprehensive overview of the benefits of air preheating in improving boiler efficiency.