SEER, which is an acronym for seasonal energy efficiency rating, is a measurement used to describe the efficient use of energy by air conditioners. The measurement is defined and regulated by the Air-Conditioning, Heating and Refrigeration Institute. It is measured in BTUs (British thermal units) per watt-hour of electric energy used in a given cooling season (during the summer months). SEER is determined by calculating a simple equation.

## Step 1

Find the BTUs per hour of your air conditioner. This value can be found either on the air conditioner itself or in the owner's manual that accompanied the air conditioner.

## Step 2

Find the number of watts used per hour for your air conditioner. This value can be also found either on the air conditioner itself or in the owner's manual that accompanied the air conditioner.

## Step 3

Calculate the number of BTUs used in the summer months. Use 1,000 hours, which equates to about 125 days or four months, to represent the late spring and summer months when air conditioners are used. Multiply the number from step one by 1,000 to get the number of BTUs used in the summer months.

## Step 4

Calculate the number of watts-hours used in the summer months by multiplying the number from step two by 1,000.

## Step 5

Divide the BTUs used in the summer months (the result of step three) by the number of watts-hours consumed in the summer months (the result of step three) to arrive at the SEER rating.