Electron-volts
An electron-volt (eV) is used in the fields of atomic and particle physics. It is the amount of energy gained or lost by a single electron when it is accelerated through an electric potential difference of one volt.
Btu (I.T.)
The British thermal unit (International Table), Btu (IT), is about 1,055 joules, roughly the energy needed to warm one pound of water by one degree Fahrenheit. In the United States air conditioners and furnaces are rated in Btu per hour.