Ending and Beginning

I’ve been thinking about heating with wood lately, specifically, how to do it more efficiently than you can with a wood stove.

I’ve been reading about Rocket Stoves, and while they look like a fantastic idea for some parts of the country, I don’t think they fit well in the Upper Midwest. I think our frequent high winds would be a problem for a Rocket, and I’ll bet you’d have it running backwards as often as you had it running the right way.

And our bitter cold winters move the dial towards the immediate heat end of the scale. When it’s as cold as it can get around here, you need lots of heat right now.

Which is not to say that you don’t need thermal mass, but you need it in addition to immediate heat.

The biggest problems that a modern, airtight woodstove has are the large amount of heat escaping up the chimney and the lack of adequate thermal mass.

Addressing our current woodstove in our current home, I can’t do a lot about the heat escaping up the chimney. The more I restrict the air entering and/or leaving the stove, the less efficiently and dirtier the fire burns. For the cleanest, most efficient use of the wood, you need fast, hot, brief fires. But to make the heat from the stove last any length of time, to even out the output to a human scale, you have to restrict the airflow. That’s a built-in paradox of the common woodstove.

The other thing that’s missing is thermal mass, and I can do something about that. I have loose bricks stacked behind and underneath the stove, and I’ve had some cinder-block size decorative red blocks on either side of it. So I’ve had some thermal mass.

Those decorative red cinder blocks had two large channels in them parallel to the long dimension of the block. Today, since I was doing some other cement work, I got together six of those blocks and filled the open channels with cement. Once the cement has cured, I will paint them flat black and put them back next to the stove. That should increase the thermal mass significantly.

I had already reinforced the floor under the stove back in 2002 when we had it put in by scabbing treated 2x8s onto two floor joists. I went down in the basement and looked at that today, and it still looks pretty good to me. I do want to put support under the foundation end of the joists, as that’s where a lot of the decay is happening. I think if I do that, I should be fine to add some substantial mass around the stove.