When looking for a new air conditioner, one is likely to be confronted by SEER and EER numbers for different makes and models. These are measurements used to evaluate a unit’s energy efficiency. However, these two numbers are different, and understanding them could help one make a better decision.

What are SEER Ratings?

SEER is short for seasonal energy efficiency rating, which is a measure of how much energy an air conditioning system uses to deliver cooling power. The benchmark is controlled by the Department of Energy, who also decide on the testing benchmarks. A higher SEER number translates to a higher score of efficiency.

What are EER Ratings?

EER is an abbreviation for energy efficiency ratio. This was an early attempt at standardizing how to calculate the efficiency of an air conditioner. The number is arrived at by dividing the input electrical wattage over the cooling created, which is measured in British Thermal Units (BTUs). Typically, EER is calculated at 50% humidity with outdoor and indoor temperatures of 95 and 80 degrees Fahrenheit respectively.

Comparison Between SEER and EER Ratings.

Previously, AC systems were only assigned EER ratings. These are still commonly used today, more on commercial HVAC units exceeding 6 tons. It was felt that this system wasn’t a good efficiency measurement system. This is because it fails to consider the time taken to reach peak efficiency. SEER measures the efficiency of a HVAC unit at varying temperatures, taking into account how these affect efficacy.

Which Rating is More Significant?

Manufacturers are mandated by law to display SEER. However, most air conditioners come with energy efficiency ratings as well. Both of these can be helpful in different circumstances.

EER is the expected efficiency at peak cooling time, usually in the middle of the summer, because it can only be measured at one high temperature. The rating is more accurate in areas where the temperature exceeds 95°F most of the time. SEER is an average which takes into account the lows and highs of the cooling pattern of a typical house. This is more appropriate for moderate climates.

When comparing different air conditioners, it’s important to use similar benchmarks. One must ensure they compare the SEER and EER to corresponding ratios. Call us to learn more about efficient heating and air conditioning options.