In 2006, the federal government gave air-conditioning purchasers a bonus — a higher required SEER rating. The Seasonal Energy Efficiency Ratio (SEER rating) measures the efficiency of air conditioners. Since January of that year, air conditioners have been required to have a SEER rating of 13 or higher. That is a 3-point jump from the prior requirement of 10. This makes air conditioners manufactured since 2006 up to 30 percent more efficient than older ones. The higher the SEER rating of your air conditioner, the more you save on electricity.
Window and Room Air Conditioners
Window and room air conditioners had the lowest SEER ratings of all prior to 2006, with an average rating of 8. However, in some ways this was understandable, because the units were not designed to cool large spaces. People still use window air conditioners for single rooms and instead of running an entire central air-conditioning system and wasting energy. Regardless of how you use one, you can be assured that it will be energy efficient and have a minimum SEER rating of 13.
Wall Air Conditioners
Prior to 2006, wall air conditioner manufacturers were selling units with SEER ratings as low as 8, but most hovered around 9.5. That was then and this is now. Today's wall units, just as all residential air conditioners, must meet the same requirements of having a SEER of 13 or higher. Wall units are a good choice for "one room" cooling if you don't want to use a window air conditioner. Wall units are used in homes and in commercial establishments.
Portable Air Conditioners
Portable air conditioners have SEER ratings that typically range from 13 to 16. This makes them comparable to the efficiency of other nonpermanent units, such as room air conditioners and wall units, but not quite as efficient as a central air-conditioning system. Portable air conditioners have wheels on the bottom to allow you to move them from room to room. They're a great choice for cooling spaces like garages, basements and spaces you don't use frequently, as an alternative to a permanent wall or window unit.
Central Air-Conditioning Systems
Central air-conditioning systems typically have the highest SEER ratings of all types of air conditioners. They generally start around 16 and range as high as 21. This can result in huge savings on your electricity bill. Each SEER point can mean as much as a 10 percent decrease in operating costs.
To get an idea of just how important the SEER rating is, compare the operating costs between two models. For example, compare the difference in operating costs between a model with a SEER rating of 16 and one with a SEER rating of 21. If the unit with the 16 SEER rating costs $300 to operate each year, and each SEER point equates to a 10 percent savings, the model with the higher SEER rating would only cost $150 to operate for a year, because it has 5 more SEER points.