Technological advances have made wood stoves considerably more efficient than those used by our forebears. Wood stoves are available either with catalytic combustion or without, but all wood stoves sold in the United States must meet EPA standards of not more than 7.5 grams per hour for non-catalytic stoves and 4.1 grams per hour for catalytic stoves. Stoves are made from a variety of material including steel, cast iron and soapstone.
Catalytic Wood Stoves
Because the particulate matter contained in the exhaust is burned at a much higher temperature, catalytic wood stoves are a minimum of 10 percent more efficient than non-catalytic stoves, depending on the application. One reason for the increased efficiency is the higher temperature that a catalytic stove reaches compared to a non-catalytic stove.
The catalytic converter in a wood stove ignites when the temperature reaches approximately 350 to 600 degrees Fahrenheit; internal temperature can reach as high as 1000 degrees. This enables the particulate matter to burn more completely in the secondary combustion chamber, which enables more even heating, which makes a catalytic stove more suitable for heating a larger area. Once the converter reaches temperature and ignites, it will remain functioning even if the temperature of the stove drops, because the converter is generating heat through the combustion of the particulate matter.
In addition, wood must be seasoned and dry before burning in a catalytic stove and some types of wood should be avoided. Full loads of wood will maximize burning efficiency and minimize door openings, which will decrease the amount of smoke that enters your home.
A catalytic stove is thermostatically controlled to regulate the temperature and equipped with fans to circulate the heated air.
Non-Catalytic Wood Stoves
Requiring less initial investment and less subsequent maintenance, non-catalytic stoves remain the most popular due their cost-effectiveness. Rather than a catalyst, these stoves use a baffle, pre-heated air and an insulated firebox to achieve combustion. In addition, a secondary combustion chamber ignites particulate matter to maximize combustion. The baffle may need periodic replacement and seals and gaskets should be inspected at least annually to ensure they are in good condition.
Although wood should always be seasoned before burning, non-catalytic stoves are more forgiving with wood that isn’t fully seasoned.
Because of advances in the design of non-catalytic wood stoves, they can approach the efficiency of their catalytic counterparts although the catalytic stoves remain the best option for heating larger areas for an extended period.
As with heating and air conditioning units, the size of wood stove purchased should correspond to the area to be heated. Using a larger stove than necessary will not provide more heat, it will simply be less efficient. All wood stoves, whether catalytic or non-catalytic, should be installed professionally. Wood stove installation is not a project for the layperson.