Our first-choice heat source at Underhill House is a combination of passive solar and the solar hot water panels that warm our floors and thermal mass interior wall. This dual-solar supply is comfortably providing all the heat we could want during even the coldest days that this not-particularly-cold winter has exposed us to, as well as almost all of the following nights. But the sun does not shine every day.
We have over 20 wooded acres to maintain on our 44 acres of land, and its ecologically-sensitive upkeep will always generate a renewable source of heating fuel. After a tree dies, the carbon it has sequestered will be released whether it decays or burns, so burning a small amount as efficiently as possible seems like a reasonable way for us to supplement our solar sources.
We didn’t really have time to put up firewood this fall while we were in the midst of our building project. Doug and I did take the time last spring to saw up the small branches left on the ground when several oaks that succumbed to Oak Wilt were felled for timbers in the house. We stacked them up on the far end of the drain field where they lay, and now we snow shoe over and grab a few arm fulls every few days. I think we will make it till things brighten up a bit and we can get by on direct solar heat.
We chose a Regency F-1100 stove because our house is small and very well insulated and we don’t need to generate much heat to warm it. Most wood-burning stoves would be overkill for us. Many cast iron stoves and those with soapstone insets are designed to absorb heat from their fires and release it slowly. Masonry stoves are the king of slow release. But we don’t need a slow release stove. Our concrete floors and thermal mass wall can hold and release heat.
What we want from our wood-burning stove is a quick fix to fill in when the sun hasn’t been shining for a few days. That’s why we liked the steel-walled Regency, which passes its heat along to the room as soon as the wood is burning.
We have also learned that Regency plants a tree for every stove sold. That doesn’t seem like a lot – I would rather they plant the equivalent number of trees to provide heat to a small house for a winter – but every little bit helps.
All Regency wood stoves have been certified by the EPA because they have a firebox designed to create airflow around the wood so it burns completely with very little ash or polluting smoke. It is supposed to burn with up to 77% efficiency and meets the DEQ Washington Phase II Clean Air Standard of 4.5 grams/hour or less.
Catalytic versus Noncat
A lot of wood-burning stoves use catalytic converters to get a clean burn. Smoke normally needs to get really hot to combust – about 1100º F. A catalytic converter gets around this by passing smoke through a ceramic honeycomb that burns smoke at about 500-550º F. This gives you the option of burning a long, slow, overnight burn and still combusting the polluting smoke.
Non-catalytic stoves use an air injection method. The draft pulls hot pre-heated air into several tubes running across the top of the fire-box. Each tube has rows of tiny holes. Heated air squirts through these holes, creating jets which fan the smoke into very active, beautiful, secondary flames that hover above the burning logs.
Regency uses this non-catalytic technology. They claim that with durable air tubes and baffles that encourage total combustion and low emissions, the Regency non-catalytic appliances burn cleaner and require less maintenance than stoves with catalytic combustors. The downside is that they don’t work well for an overnight fire, which we don’t need because of our well insulated walls and heat retaining floors.
The EPA has created a consumer information sheet on how to reduce air pollution from residential wood burning. Check it out here.
Categories: Eco architecture, Underhill House
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