Understanding EAEER: Energy Adjusted Annual Energy Efficiency Ratio

EAEER is a less frequently used but the most accurate energy efficiency ratio for air conditioning systems. Despite being seldom specified on the specs sheets, it is the most realistic air conditioner energy efficiency ratio (more than SEER, EER, CEER, IEER).

EAEER stands for Energy Adjusted Annual Energy Efficiency Ratio. In contrast to more well-known SEER and EER ratings, the EAEER takes into account these two vital factors:

  • Outdoor temperature. During the year, the outdoor temperatures vary significantly (from 100°F or even more in the summer to below 0°F in the winter).
  • Humidity levels. Humidity levels are higher in the summer (50% or more) and lower in the winter (30% or even lower). The EAEER accounts for these relative humidity levels as well.
Energy Adjusted Annual Energy Efficiency Ratio accounts for outdoor temperature and humidity levels
Energy efficiency of an AC unit depends primarily on the outdoor unit. It’s efficiency, of course, depends on outdoor temperature and outdoor humidity levels as well; they are both accounted for in EAEER rating (EER and SEER don’t account for that).

EAEER is calculated on an annual basis. It depends on how much cooling output our air conditioner produces year-round and how much electricity we use to run it.

Example: Let’s say that a 36,000 BTU/h air conditioner produced 20,000,000 BTU per year. To run it, we used 2,000 kWh of electricity. We can calculate the EAEER rating using this formula:

EAEER Rating = 20,000,000 BTU/h / (2,000 kWh × 1,000) = 10 EAEER

This AC unit has a 10 EAEER rating.

We can write the general EAEER formula like this:

EAEER Rating = AC BTU Output Per Year / (Electricity Usage (in kWh) × 1,000)

As we can see, the EAEER rating not a theoretical metric; it is a practical metric. And therein lays the problem.

How To Measure EAEER Rating For An Air Conditioner?

Calculating EER or SEER rating, for example, is quite simple since both are based on theoretical calculation.

For the EER rating (Energy Efficiency Ratio), we just divide the max. cooling output (BTU/h) by max. power draw (wattage).

For the SEER rating (Seasonal Energy Efficiency Ratio), we measure the EER rating for partial loads (at 25%, 50%, and 75% output) and full load (100% output) and then use a weighted-average calculation that, in most basic terms, presume the AC unit runs, on average, at 58% output.

Now, for calculating EAEER rating we need to measure these two very-difficult to measure metrics:

  • Annual cooling output (BTUs per year).
  • Annual energy usage (kWh per year).

Both are incredibly difficult to measure accurately; this is why the EAEER rating is not used very often.

yearly electricity usage for eaeer rating calculation
To calculate the EAEER rating, we have to know how much electricity did our AC unit use throughout the year.

The key advantage of this is that the output and energy usage throughout the year depends on there 3 key metrics that are practically accounted for in EAEER ratings (and are at best theoretically evaluated in EER and SEER rating):

  • Average AC load. With EER, we have a 100% load, and with SEER, we have a 58% average load. The annual average cooling output can be anywhere between 0% and 100%. The measured annual cooling output tells us exactly what yearly average load the AC unit was running at.
  • Outdoor temperature. AC energy efficiency depends on the outdoor temperature; by measuring the annual energy usage, we account for the varying outdoor temperature.
  • Humidity levels. AC energy efficiency also depends on the humidity levels – both outdoor and indoor humidity levels. Measuring the yearly electricity usage also accounts for these humidity levels.

All in all, the EAEER or Energy Adjusted Annual Energy Efficiency Ratio is the most realistic measure of energy efficiency for any air conditioner. However, it is also one of the most difficult to measure and is thus very seldom used or specified on the air conditioner specification sheets.

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