We don’t need to remind you how cold it is out there. And we probably don’t need to remind you that we’ve got a wide variety of heaters to make you more comfortable. Our Heating & Plumbing category’s got fireplaces, wood burning stoves, water heaters & pellet stoves. If you’re shopping around for a heating source, however, it’s important to mind your BTUs.

You’ll often see a BTU number in ads for heaters and air conditioners. BTU stands for British Thermal Unit, and it’s a standardized measurement of heat. In the case of heating units, it indicates the amount of energy needed to heat one pound of water 1° Farenheit. Because it’s a standard measurement, it’s a great way to compare the capabilities of various heating systems.

BTUs are also used to measure the amount of heat generated by different fuels. For example, propane is approximately 15,000 BTUs per pound, while charcoal is just about 9000 and wood is around 7000. If you happen to be of a scientific bent, you can figure out exactly how much fuel you’d need to, say, grill a hamburger.