Buying a new air conditioner can actually save you money in the long run. New models are as much as 30% more effective than systems that are only 10 years old. When shopping for a new AC, look for the SEER (Seasonal Energy Efficiency Ratio) rating. The higher the rating, the more energy efficient the system is. When your AC is energy-efficient, your utility bills go down, saving you money. And as a bonus, there are many rebates available for new AC models.