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What is a BTU?

Shopping for a new furnace and wondering what are BTUs? BTU stands for British Thermal Unit – a value traditionally assigned to heat. Technically, a single BTU is the amount of energy that is necessary to increase the temperature of one pound of water by one degree Fahrenheit at sea level. As far as a heating system goes, BTUs refer to the amount of heat that a furnace is able to output.

When it comes to furnaces, the larger the square footage that needs to be heated, the more BTUs you’ll require. For example, it’s suggested that a 1,500 square foot home has a furnace that is able to output 45,000 to 90,000 BTUs.