SEER (Seasonal Energy Efficiency Rating)
Central air conditioners and heat pumps are most commonly rated according to their Seasonal Energy Efficiency Rating (SEER). SEER indicates the amount of energy needed to supply a specific cooling output.
Comparing SEER and EER in Rating Air Conditioners
The Energy Efficiency Rating (EER) of a particular cooling unit is the ratio of output cooling energy to input electrical energy at a given operating point. The Air-Conditioning and Refrigeration Institute standardized this rating, which reports central air conditioning efficiency at a 95 degree F outside temperature and an 80 degree F inside temperature.
EER is measured at one set of conditions, while SEER is a seasonal average, measured over a range of conditions. Since air conditioning units don’t perform comparably at all temperatures, there will be differences between the single condition EER testing uses, and the range of weather conditions SEER testing uses. SEER measures the expected overall performance for a typical year’s weather in a specific location.
For areas of the country where it is 95 degrees F or higher most of the time the air conditioner is on, the EER is usually more accurate. More moderate climates use SEER, which provides an average, taking into account highs and lows of a home’s cooling pattern. The important thing is to compare one air conditioner’s EER to another’s EER, or SEER to SEER. Comparing the EER of one model to the SEER of another model will not be accurate.
Current Recommended SEER
As of January 2006, a residential air conditioner must have a SEER of at least 13 to be sold in the United States. Air conditioners with a rating of less than 13 manufactured before January 2006 may still be sold and installed, and replacement parts and services are still available, so the standard does not require that homeowners change existing units. For most homeowners, the standard SEER 13 units are most cost effective, but the longer the cooling seasons and the higher the electricity costs, the more that higher SEER units are reasonable. Higher efficiency models can have a SEER of up to 23.
SEER and Energy Savings
More efficient central air conditioning models provide substantial energy savings. By upgrading from SEER 9 to SEER 13, for example, the power consumption is reduced by 30% (equal to 1 – 9/13). It is claimed that this can result in an energy savings of up to $300 per year depending on the usage rate and the cost of electricity.
New Energy Minimum Standards (January 1, 2015)
Regional climate differences play a part in the US Department of Energy’s revised energy minimum standards. The regional approach recognizes that there is little cost benefit to having a very high SEER air conditioning unit in the northeastern region of the United States, where cold weather often prevails. Starting January 1, 2015, central air conditioners installed in the southeastern and southwestern regions of the United States must be at least 14 SEER. Central air conditioners installed in all other states outside of the southeastern and southwestern regions must continue to be a minimum of 13 SEER.
Heat pumps have a minimum SEER of 14 across the United States beginning in 2015.