What do the BTUs of a gas furnace do?

BTU, which stands for British Thermal Unit, is a unit measurement often used to list how much energy a gas furnace or other heating unit produces. One BTU is the amount of energy required to heat one pound of water one degree Fahrenheit.

Since power is an important component when discussing heating and cooling systems, the BTUs per hour rating is commonly used when discussing gas furnaces and other heating units. Although metric measurements are popular around the world in other fields, BTU and BTU/h are still commonly used when dealing with heating and cooling units even in places that use metric measurements.