The efficiency of central air conditioning systems is rated by a Seasonal Energy Efficiency Ratio (SEER). SEER ratings typically range from 13 to 23, with the highest numbers indicating the more efficient units offering the most energy savings. Great strides have been made in the last 10 years to increase the efficiency of new air conditioners and heat pumps.
The typical SEER rating of air conditioners manufactured before 1992 was about 6.0. In 1992, the federal government established the minimum cooling efficiency standard for air conditioning systems installed in new homes at 10 SEER. The minimum SEER value changed again on January 23, 2006 to 13 SEER. To be considered as high-efficiency units, air conditioners must have a SEER rating of at least 14. The SEER rating is usually shown on a yellow and black EnergyGuide sticker attached to the outside unit of the air conditioner. Recently different minimum SEER standards have been adopted to different regions of the United States.
Central air conditioners that are in the top 25 percent of efficient models may carry the Energy Star® label. To qualify, air conditioning systems must have a minimum SEER efficiency level of 14. Additionally, Energy Star® models must also have a minimum Energy Efficiency Ratio (EER) of at least 11.5 for split systems, and of at least 11.0 for single-package models. Air conditioners that bear the Energy Star® label may be twice as efficient as some existing systems.
Heat pumps also have heating efficiency ratings, indicated as a Heating Seasonal Performance Factor (HSPF). In general, the higher the HSPF rating, the less electricity the unit will use to do its job. Both HSPF and SEER are a general indication of how many Btu’s a system produces per KW of electrical consumption.
In 1992, the federal government established the minimum heating efficiency standard for new heat pumps at 6.8 HSPF. Most heat pumps manufactured before 1992 had HSPF ratings below 5. The minimum HSPF standard changed again on January 23, 2006 to an HSPF of 7.7. Today, an HSPF of 8.2 or higher is considered “high-efficiency”; the maximum available is 13 HSPF possible with Carrier Greenspeed heat pump systems.
High-efficiency central air-conditioning heat pumps can also qualify as Energy Star models. In addition to meeting the minimum SEER and EER requirements, they must also meet minimum HSPF requirements of 8.2 for split systems and 8.0 for single-package models.
Higher efficiency units usually cost more to purchase initially, but save money in the long run on operating costs.