BTU is short for British Thermal Units.

BTU is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.

**Formula to calculate BTU.**

The flow rate is measured in gallons per minute.

**Example:**

Suppose the rate of flow of water i your household is 6 GPM, calculate the BTU if the leaving process temperature is 27 degree Fahrenheit and the entering process temperature is 25 degree Fahrenheit.

Therefore, your BTU is 6,004.8.