Before the widespread use of fossil fuels, most people relied on burning wood to heat their homes. According to the United States Department of Energy, about 90% of Americans used wood as their primary fuel before the 20th century. As other fuel sources and compatible appliances became available, this figure dropped significantly, reaching just 1% by 1970.
The energy crisis of the 1970s sparked a revival in wood as a heating fuel, recognized as a renewable energy source when harvested from sustainable forests. Alongside this trend, fuel pellets containing wood have gained popularity. This shift has led to a growing range of modern appliances designed for heating with wood, pellets, or other biomass fuels. Some pellet appliances can even burn unconventional materials like dried cherry pits, nutshells, corn kernels, soybeans, and beet pulp.
Choosing an Energy-Efficient Heating Appliance for Your Home
Selecting a wood or multi-fuel stove requires careful consideration to ensure it is energy efficient. A common mistake is choosing a unit too large for the space, thinking bigger is better. However, an oversized appliance often burns at a low smolder to avoid overheating, which is wasteful and causes pollution. Conversely, an undersized unit won’t adequately heat the room.
Beyond size, consider the heater’s capacity to warm a specific area and its environmental impact. When shopping, ask about British Thermal Units (Btu), which indicate how much space an appliance can heat. For example, a 42,000 Btu unit heats approximately 1,300 square feet, while a 60,000 Btu unit can warm 2,000 square feet. The heater’s location and your home’s construction also affect heat distribution.
Avoiding Air Pollution
Wood burning can release harmful compounds, including organic gases and carbon monoxide. Some local authorities ban wood-burning appliances, while others require certification from the US Environmental Protection Agency (EPA) or similar bodies. Manufacturers incorporate catalytic combustors to burn combustion gases at lower temperatures, cleaning exhaust gas and generating more heat. These high-efficiency appliances are non-polluting and safer, as they reduce harmful chimney flue deposits. If you have an older appliance, consider retrofitting a catalytic damper in the flue collar.
Types of Wood-Burning Appliances
Various appliances are available for burning wood or pellets, including:
- Fireplace inserts and high-efficiency fireplaces: These enhance the efficiency of old masonry fireplaces, fitting into existing structures with a flue collar. Inserts should be as airtight as possible.
- Wood stoves: Modern catalytic stoves and inserts use wood gasification technology to burn both wood and combustible gases, improving efficiency.
- Masonry heaters: These produce more heat and less pollution, featuring a fireproof firebox lined with refractory concrete or firebricks that withstand temperatures over 2,000°F (1,093°C). They have long, twisting smoke channels but take longer to heat up compared to wood fireplaces or stoves.
- Pellet fuel appliances: Exempt from EPA smoke-testing in the USA due to their efficiency and low pollution, these can be direct-vented without a chimney. They come as freestanding stoves or fireplace inserts.
Selecting the Right Appliance
With a wide variety of wood-burning appliances available, shop around for price, style, and quality. Choose EPA-certified units that qualify for energy or biomass tax credits. Notable manufacturers include:
– United States Stove Company (www.usstove.com): Established in 1864, specializing in wood and pellet stoves.
– Kuma Stoves (https://kumastoves.com/): Producing EPA-approved wood stoves and inserts for over three decades, meeting strict Washington State standards.
– Napoleon Fireplaces (www.napoleonfireplaces.com): Offers a range of stoves and fireplaces with patented technology exceeding EPA standards. Their Timberwolf line (www.timberwolffireplaces.com) includes units approved for mobile homes.
– Osburn (www.osburn-mfg.com): Originally focused on wood stoves, now offering inserts and other heaters, serving markets from the USA to Australia.
– Regency (www.regency-fire.com): Manufactures EPA-certified wood stoves, inserts, and fireplaces eligible for US biomass tax credits.
Selecting Wood for Your Appliance
Never use wet wood. The best firewood is harvested in spring and dried through summer, with a moisture content of 20% to 25% by weight. Overly dry wood can smoke and emit gases, reducing heat and polluting the air. While all wood species produce similar heat levels, denser wood burns longer and costs more. Aspen is ideal for naturally cleaning chimneys. Pellet fuels, with 5% to 10% moisture, produce less heat when made from wood compared to agricultural waste but generate less ash.
