Convert SEER to EER (Calculator + Conversion Table)

The need to convert SEER to EER occurs when comparing two air conditioners – one listed by SEER and the other by EER.

What are SEER and EER?

SEER and EER are measurements of air conditioner cooling – how efficiently the unit uses electricity to move heat from inside your home to outdoors where it is dispersed.

SEER is the Seasonal Energy Efficiency Ratio, measuring the average efficiency of a unit in conditions experienced throughout a typical cooling season, from warm to very hot.

EER is the Energy Efficiency Ratio, and it measures efficiency at a single point in time with conditions of 95F outside, 80F indoors and 50% humidity.

Here is our “Convert SEER to EER” Calculator which can help you get the result quickly.

SEER to EER Calculator

SEER to EER Calculator

Convert SEER to EER

All standard split system air conditioners are measured in SEER. However, many are now also listed by their EER rating, and that’s very helpful.

Geothermal heat pumps are rated by EER for cooling.

If you were attempting to compare the long-term operating cost of the units vs the upfront equipment cost, you would have to convert SEER to EER to compare “apples to apples.”

For example, let’s say:

An air to air Carrier heat pump has an 18 SEER rating and costs $10,000 installed

An open loop Carrier geothermal heat pump system has a 29.5 EER rating and costs $24,000.

When you combine equipment cost and operating cost, which is the better value over 20 years?

To find out:

1. Convert SEER to EER

2. Determine percentage of savings with the geothermal in annual energy bills

3. Consider total energy use and savings over 20 years with the geothermal

4. Compare total costs

OK, let’s do the math:

1. Convert SEER to EER by multiplying SEER by .875.

18 x .875 = 15.75 EER

2. Determine % savings by dividing 15.75 by 29.5.

The Carrier geothermal heat pump uses 53% as much energy as the standard / air source heat pump, so you’ll save almost 50% in energy costs.

3. Consider use and savings over 20 years.

If you were expected to spend $600 on cooling each year with an air source (standard) heat pump, you’d spend $320 with the geothermal. That’s for a moderate climate. In very hot climates, you might spend as much as $1,000 with the air source Carrier heat pump and $534 with the geothermal.

Over 20 years, the savings would be $6,400 in the moderate climate and $10,380 in the hot climate.

Those are just the air conditioning numbers. You’d have to do the same calculations for heating and combine the savings. When AC-only is considered, the geothermal heat pump isn’t worth it – and in warm climates with very little heating required, it also probably isn’t worth it.

Bottom Line in SEER to EER Conversion

You know your purposes for converting SEER to EER. That’s how it is done. Plug the numbers into our SEER to EER calculator or do the math on your own.

Our SEER to EER conversion chart shows common SEER ratings and their EER equivalent.

SEER Rating

EER Rating


11.38 EER


12.25 EER


13.13 EER


14.00 EER


14.88 EER


15.75 EER


16.63 EER


17.50 EER


18.38 EER


19.25 EER


20.13 EER


21.00 EER


21.88 EER


22.75 EER

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