BTU: A Measurement of Heat Energy

What is a BTU?

A British Thermal Unit (BTU) is a unit of energy used to measure the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. It is a commonly used unit in the heating, ventilation, and air conditioning (HVAC) industry, as well as in other applications where heat transfer is involved.

How is a BTU Calculated?

The amount of heat energy required to raise the temperature of a substance by one degree Fahrenheit is known as its specific heat capacity. The specific heat capacity of a material is measured in BTUs per pound per degree Fahrenheit (BTU/lb-°F). To calculate the number of BTUs required to raise the temperature of a given mass of a substance by a certain number of degrees, the following formula is used:

BTUs = mass (lb) x specific heat capacity (BTU/lb-°F) x temperature change (°F)

Example: Calculating BTUs for Steel

For example, if you want to calculate the number of BTUs required to raise the temperature of 100 pounds of mild steel by 100 degrees Fahrenheit, you would use the following formula:

BTUs = 100 lb x 0.122 BTU/lb-°F x 100 °F

BTUs = 12,200 BTUs

Conclusion

BTUs are a useful unit of measurement for quantifying heat energy. They are commonly used in the HVAC industry and other applications where heat transfer is involved. Understanding how to calculate BTUs is important for properly sizing and operating HVAC systems and other equipment that uses heat energy.