The Seasonal Energy Efficiency Ratio, or SEER, is a standard of measuring a unit's energy usage and efficiency when running. While older air conditioners may only have a SEER of 6 or 10, the new minimum SEER allowed by the US Department of Energy is 13. The higher the SEER number, the more efficient the unit and the cheaper it is to run because it will use less electricity.
Higher SEER air conditioners may be more expensive up front, but they can save you quite a bit of money (to the tune of $20 or more) on your electricity bill every month. For example, an old air conditioner with a SEER of 6 may cost as much as $150 to run a month, while newer models with a rating of 14 or more may only cost $90 a month. These are estimates so rates in your area may vary, but it's easy to see that a machine with a higher SEER rating is a worthwhile investment.Look for a Humidity Control:
Humidity makes the air feel heavy, wet and hot even when the air temperature itself may only be in the low 80s. At higher air temperatures, humidity can make life feel pretty miserable indoors or out.
If you live in a clime that has humid summers, finding an air conditioner with a humidity control will not only make things more bearable during muggy summer days and nights, but it could save you money, too. An air conditioner that has a specific setting for humidity control will not have to work as hard or run as much to properly cool a room than a unit without this option.Find a Unit That Has a Modulation Control:
Modulation control is just as important as SEER ratings or humidity settings on new air conditioners. Many older models had only two fan settings: low and high. Newer models, however, come with various speeds and have other options for adjusting what temperature to cool the room to and what speed to run the internal fan at. Once the desired temperature is reached, air conditioners with modulation control will shut off or go on "pause" mode until the room begins to get too warm again. This feature can save homeowners money on their energy bill as it is far more efficient than having a unit running longer or harder than it needs to.