Choosing the Best Firewood: Hardwood vs Softwood for Efficient Heating

[@jfess1911]

Dense woods to provide more heat per volume, but since the 1980's most home woodstoves have been able to burn softwoods like pine cleanly by burning off the smoke with a catalyst or by adding preheated air for secondary combustion. They had to pass air emissions tests with Douglas Fir. Many people don't realize it, but, woodstoves have been regulated by the EPA since 1988 and in Oregon for a number of years earlier. Some of the old wisdom still applies If you are using a woostove over 40 years old or have an exempt fireplace insert or fireplace.

[@johndoeboston123]

Yeah, they pass the EPA test, but softwoods still gum up and destroy your catalytic converter over time. So they say.

[@jfess1911]

@@johndoeboston123 Many years ago I did field testing on those stoves. It was interesting how much extra heat was in that smoke that got burnt, about a third more. We tracked wood use. The trick to prevent gumming up was to run hot enough when loading with wood for the catalyst to "light off" (about 500°F) which would burn off tars. If you just filled the stove with wood and let it smolder without initial cat heat-up, it wouldn't burn cleanly . The main issue we found was poor design of some stoves. They had undersized catalysts and/or did not protect them from flame impingement, causing catalytic converters to get over 1600°F and damage themselves. The better designs did not, at least over the years of the study. At some point, many would require catalyst replacement. I preferred the non-catalytic types and used one for a couple of decades. The main issue with those was that they had to run hot enough to keep a flame, reducing maximum burn time. If you like to look at flames, the smaller units generally did a better job of keeping the "glass" window clear without overheating the average room.