Modern Outdoor Furnaces - Are They the Answer to Your Heating Problems?

Outdoor furnaces are becoming popular because they offer the convenience of long burn times, the safety of removing the combustion process from inside the home, and because they can be installed to provide heat and hot water to more than one building on your property. Outdoor furnaces are not wood-burning stoves. Many units are about the size of a backyard storage shed and burn wood and/or corn to heat water or air that is pumped back into your home. They can be used with existing heating systems such as radiant floor, boiler or a forced-air furnace and also heat domestic water. Outdoor furnaces are not intended to be the only source of heat. It is recommended that a back-up system is in place to prevent damages caused by lack of heat. 

Outdoor furnaces are best suited for rural applications where the furnace can be located at least a minimum of 100 feet from other residences although some smaller, well insulated models  can be located right next to your home or even in an outdoor shed or garage. The prevailing wind direction should always be considered in the installation, and owners and installers should follow best practices. Wood may not be the best fuel choice in densely populated urban areas where automobile exhaust and other pollution already negatively affect the air quality, but in suburban, small town, and rural areas, wood can be used without damaging the air quality of your neighborhood.

Although they emit some smoke and carbon dioxide, outdoor furnaces are still an environmentally responsible method of heating. Outdoor furnaces burn renewable, biomass fuels such as wood and corn. These burned corn and wood emissions are carbon neutral, meaning they don't generate a net increase in greenhouse gas emissions as do fossil fuel generated electricity, natural gas, fuel oil, kerosene, liquefied petroleum gas, and coal. The reason for biomass fuel's carbon neutrality is that whereas fossil fuels are mined out of the earth and then burned, contributing carbon to the atmosphere that would not otherwise have been there, biomass fuels contribute carbon dioxode that would have been emitted anyway through the process of decomposition, thus making biomass fuels carbon neutral.

Both wood and corn pellets are very similarly low in price and burn very efficiently. Wood pellets are often manufactured (recycled) from wood by-products. When you burn corn or wood it produces primarily ash. The best outdoor furnaces feature 100% steel firepots (or fireboxs). A firepot and agitator ensure, in combination with the inlet airflow, complete burning of the fuel, with almost no ash production.

Outdoor furnaces remove the dangers of wood stove fires in the house often resulting in lower insurance rates. With indoor furnaces and wood burning stoves you have to deal with the smoke, ashes, odors and soot build on the walls and ceilings inside your home. This soot, called creosote, contains carbon monoxide and other organic gases, particulate matter, chemicals, and some inorganic gases. Some of these compounds, such as aldehydes and phenols, are toxic, while others, like benzopyrene and cresols, are known carcinogens. 

Depending on the size of the unit, most outdoor wood furnaces need to be loaded only once or twice a day. Outdoor corn furnaces also burn very clean and can sustain heat for days on a single load of corn. Keeping the furnace free from rust and creosote is the most important thing for proper maintenance.