The main thing you should consider when purchasing an A/C is the Seasonal Energy Efficiency Ratio (SEER) rating for the unit. The SEER rating is designed to estimate the energy efficiency level of the system. SEER values may range from 6 to 23 and are counted by dividing the cooling output amount of the unit by the amount of energy consumed during the process of cooking. This standardized rating is used by every major manufacturer, and in general, higher SEER values indicate greater device efficiency. Call us if you need more information.