Clearing the air about combustors: By re-burning fuel elements in the smoke, combustors reduce your need for wood, increase heat output, reduce creosote formation and lower emissions. New, longer lasting retrofit catalytic combustors can improve wood stove efficiency by 10 percent to 25 percent.

Besides substantially reducing the amount of wood needed during a heating season (if you rely heavily on a wood stove), these catalytic combustors can also cut back on creosote formation and air pollution by as much as 80 percent. Like the catalytic converter in your car's exhaust system, the combustor works by burning fuel elements in the smoke, thereby lessening the potential for acid rain and chimney fires.

Stoves with catalytic combustors should have a main body thickness of a minimum of 1/4-inch plate steel or cast iron. Its bypass plate should be at least 5/16-inch thick and grip a piece of thin paper tightly when closed. Also important is the mechanism installed to protect the combustor from direct flame, which will prevent premature wear. This flame protector is sometimes placed in front of the catalytic combustor, while other manufacturers place the combustor in the rear of the stove, or thirdly, may use a series of chambers.

Though the catalytic combustor needs little upkeep, any ash that collects on the combustor may be cleaned gently with a soft brush. Its internal "honeycomb" part never needs cleaning, but should be replaced normally within two to three years. Some signs of needed combustor replacement are creosote build-up, excessive chimney smoke, and a general sluggish stove operation.

Noncatalytic Combustor Stoves ("noncats") burn wood within a heavily insulated firebox that ensures a more thorough combustion. Residual gases and soot particles are burned off in a secondary combustion chamber. Without a combustor to maintain, noncatalytic stoves do not require the level of care as catalytic stoves.

When shopping for a noncatalytic combustor stove, the important factors to look for are the materials and construction type used. They will determine the cleanliness and efficiency of the stove's operation for years to come. The body of the stove should be constructed with a minimum of 1/4-inch cast iron or plate steel. The very important baffles, which are located in the interior roof, should be constructed with a minimum of 5/16-inch plate steel and have support beams that are v-shaped to resist warping.

-- Tips courtesy of HomeAdvisor.com