British thermal units (Btu) are a standard unit of measurement for energy, commonly used in the United States to quantify the energy content of fuels and the amount of energy used in heating and cooling systems. One Btu is the amount of energy needed to raise the temperature of one pound of water by one degree Fahrenheit.
In the context of measuring household energy across multiple fuel types—such as electricity, natural gas, heating oil, and propane—Btu’s provide a common metric that allows for easy comparison of energy consumption and efficiency. By converting all energy use to Btu’s, it’s possible to assess and compare the energy efficiency and cost-effectiveness of different fuels and appliances, regardless of their source or form.