comparing seer vs eer

When looking to purchase or upgrade any air conditioners or heat pumps, you should be aware of both the Seasonal Energy Efficient Rating (SEER) and Energy Efficiency Ratio (EER) requirements. The Seasonal Energy Efficiency Rating measures the efficiency of a system over a period of an entire season, while the Energy Efficiency Ratio measures the efficiency of a system at a specfiic outside temperature.

The difference is obvious - EER is taking a measurement at one point of time and specific temperature, while SEER is taking measurements over an extended period of time with variable temperatures. It's also important to note that most residential units use the SEER rating as a standard. There is a difference in degree of difficulty when trying to take these measurements. For example, taking the SEER measurement is more difficult because you must predict weather conditions, while the EER uses a direct approach, with no predictions necessary.