BTUs of Wood Stoves Based on Sizes of Houses

British Thermal Units

• The British thermal unit, or BTU, is a measurement of heat. A single BTU is roughly equivalent to the heat given off by a kitchen match or the heat required to raise the temperature of a pint of water by one degree Fahrenheit. BTUs are used to measure the heating capabilities of wood stoves and fireplaces, as well as those of appliances burning other types of fuel.

Why BTUs Matter

• Each home has its own heating needs and purchasing a wood stove that closely approximates those needs is paramount. A stove that is too weak will, of course, be incapable of fully heating your house on the coldest of winter days. An overly powerful stove is just as bad. To keep your home from becoming too warm, you will have to keep the stove at a low smolder, a technique which is fuel-inefficient and releases large quantities of pollutants into the atmosphere.

Determining Your Needs

• The number of BTUs needed will depend on the size of your home. The U.S. Department of Energy recommends a 60,000 BTU stove for a 2,000 square foot house and 42,000 BTUs for a 1,300 square foot house. You can find out your home's requirements using any of the BTU calculators available online --- most of these are designed for those using gas furnaces, but the math holds true no matter your heating source.

Calculating Stove Output

• Many modern wood stoves come with a BTU rating clearly marked on the packaging or an exterior panel. Purchase one that is within 1,000 BTUs of your home's needs for best results. If you're using an older stove, you can use Hearth.com's burn time calculator to find its BTU output. Provide the calculator with the firebox dimensions and type of your stove and you'll receive detailed data that takes burn speed and wood density into consideration.