Catalytic and Non-Catalytic Wood Stoves

Oct 30, 2007- Wise Heat

Catalytic and Non-Catalytic refers to the two methods employed in new stoves to keep them running clean and efficiently.

"Cats" use catalytic combustors, and "noncats" recirculate the smoke and reburn it. Normally, smoke isn't completely consumed in the burning process, because some wood gases require temperatures as high as 1,200F to burn wood efficiently.

A catalytic combustor lowers this required temperature to 600F, achieving a long, slow, controlled combustion that burns off the smoke that otherwise would leave the chimney as dirty, wasted fuel. The catalytic combustor needs minimal cleaning. If ash collects on the face of the com- bustor it can be cleaned with a soft brush. The internal "honeycomb" portion should never be cleaned with anything. It needs to be replaced after two to three years of normal use. Sluggish stove operation, creosote build-up and excessive smoke coming out of the chimney signal the need for a new combustor. Noncatalytic (recirculating) stoves use a heavily insulated firebox. This insulation keeps the heat in, creating a hot environment that encourages more complete combustion, with a secondary combustion chamber to burn off more gases and soot particles. "Noncats" don't need as much attention as "cats," primarily because they don't have a combustor to maintain. Due to the new regulations, both types should provide comparable long-term performance.