Enter the total cooling seasonal load and the cooling seasonal energy consumption into the calculator to determine the ISEER rating.

## ISEER Rating Formula

The following equation is used to calculate the ISEER Rating.

ISEER = CSTL / CSEC
• Where ISEER is the ratio of total load to total consumption
• CSTL is the cooling seasonal total load
• CSEC is the cooling seasonal energy consumption

To calculate ISEER, divide the cooling seasonal total load by the cooling seasonal energy consumption.

## What is ISEER Rating?

Definition:

ISEER is a measure of the ratio of the amount of heat an air conditional units can remove per unit of energy consumption.

## How to Calculate ISEER Rating?

Example Problem:

The following example outlines the steps and information needed to calculate ISEER Rating.

First, determine the cooling seasonal total load. This is measured to be 500 BTUs.

Next, determine the total energy consumption. This is measured to be 200 watts.

Finally, calculate the ISEER using the formula above:

ISEER = CSTL / CSEC

ISEER = 500/200

ISEER = 2.5