If you have ever installed a heating system or even just picked out a boiler or air conditioner, you should be familiar with the term BTU. BTU stands for British Thermal Unit. One BTU equals roughly the amount of heat needed to raise the temperature of a pound of water 1°F, equivalent to about 252 calories, 778 foot-pounds, or .3 of a watt-hour.
The number of BTUs needed to heat a space depends on several factors. In addition to square footage, climate and insulation quality play a major role. Use the BTU Calculator at SupplyHouse.com to get a good idea of how many BTUs you need to heat your home.