Barn News

Supercharging a Wood/Coal Stove

So far I’ve talked about two-and-a-half of the three legs of the stool I am sitting on in order to cope with a cold shop: 1) Isolation (reducing the drafts and minimizing the heated volume), 2) Insulation (via fixed thermal windows and a cocoon of R-43 XPS panels) and 3.1) Generation (of heat with a kerosene heater).  Today I want to close out this blog arc with the 3.2) Generation of heat with a wood/coal stove section.


My cast iron heat stove is a Coalbrookdale Severn unit, a 500-pound British product that is no longer being manufactured.  I mentioned this in an earlier blog about heating with coal.  There is a lot of chat about this stove on-line, and there seems to be widely divergent opinions about it — its owners either love it or hate it, no one is ambivalent.  My pal Tony scored this one for me during a renovation project he was doing, where the client wanted this stove removed and the preceding fireplace rehabilitated.  Tony’s crew installed this in my barn basement last winter.  I decided to put it there for several reasons.

First, I did not want to sacrifice floor space in my main shop to the wood stove, which if used perfectly safely and some amount of fuel storage would have consumed more than 10% of the available shop space.  So, it was just a preferential space expression on my part.  Second, having an open flame heat source in the middle of a woodworking shop was something my insurance company was hesitant about.  On that point keeping it in the concrete block basement with a packed gravel floor made sense.  Another reason is that the space in the basement is not to be an unused space, in fact it will be my machine shop.  Nothing is colder than handling tons of freezing cold iron, so having the main heart source down there is a big plus.  Finally, heating that space will keep the floor in my shop warmed, so I won’t be standing on a cold floor all the time.

Using the stove, especially for coal, is a bit tricky.  The firebox is really small, so if I am burning wood I need to tromp down stairs every 90 minutes or so to put more wood in.  I am still trying to get the hang of using coal.  There must be a special technique for igniting anthracite, of which I have some inventory, but once it gets going it goes gangbusters.

Still, I was wrestling with the fact that the heat distribution from the stove was pretty much passive, and would take almost all day to get the studio warm enough.  I didn’t want a complicated, dynamic distribution system that would need a lot of gadgeteering and monitoring/maintenance, but I definitely needed to find a better way to get the heat from the firebox into the studio a lot quicker.


I recently acquired and installed an accessory to enhance the wood/coal stove dramatically, namely this heat recovery unit that fits in line with the stove pipe.  It has been thus far a remarkable addition to the heating system for the shop.  Once the stove gets heated up, the thermostatically controlled fan in the heat recovery unit kicks in and it starts gently blowing hot air into the shop space, and if I keep the fire in the stove going, it keeps the shop warm enough that I generally peel off my vest in short order.


So, my typical shop day heating cycle begins with me lighting the kerosene heater when I first get there, then trekking downstairs to start building up the heat in the cast iron stove, then back up to the studio to start working.  Before I know it, the fan for the heat reclaimer comes on and I soon turn off the kerosene heater as the temperature climbs quickly to about 60 degrees, which suits me just fine.  With a little fire maintenance throughout the day I am entirely comfortable working in the studio.  Once I get the real hang of the coal fire, I can probably cut down on the fire maintenance to once in the morning and once at night.