What is a BTU?
BTU stands for the British Thermal Unit (BTU). It is a unit of heat energy in the inch-pound unit system, which is common today in the United States. The Btu is defined as the amount of heat necessary to raise the temperature of one pound of water one degree Fahrenheit from 58.5 to 59.5.
A BTU is commonly used to indicate the heating and cooling capacity of a system, heat losses, and heat gains. To give an example of system capacity, a 10,000 BTU window air conditioner is capable of removing 10,000 BTU’s of heat per hour. To give an example in terms of heat gains, the typical heat gain added to a room by a person at rest is about 230 BTU/hour.