In addition to my wood stove and woodpile, I keep a small stockpile of coal for emergency heating. I'm contemplating getting a bit more and finishing restoration of a couple of wood/coal stoves that were given to me.

Advantages:
- cheap like dirt
- slow, even, long-lasting heat
- cooler flue temperature; reduced fire hazard
- can be stored indefinitely
- very compact
- no explosion hazard in storage

Drawbacks:
- burns best in a stove designed for coal
- not suitable for wood stoves without some modifications
- small risk of spontaneous combustion
- some people find the smell objectionable

Has anybody else used or considered coal as an emergency heat source? How do you plan to use it?

Cheers,
Doug

Just wondering, why is it not suited for wood stoves?

I have a wood stove in the garage and I go through a lot of wood, never considered coal because I have a friend that owns a lumber yard and I get all the wood scraps he generates for free. Nothing like free heat. The garage has run on free heat (wood) for 25+-years.

I have an open coal fire in my living room. It's not just for emergencies - I light it most evenings and it is burning now. I probably should burn wood instead, but I've not found a good local supply and coal is cheap and easy.

As I understand it, coal burns very differently than wood. It requires an enormous draft, much more than a wood fire. A modern, efficient wood stove would be unlikely to provide enough air unless you kept the door cracked open.

Every coal stove I've seen, ancient or modern, holds the coal on a massively heavy grate so the draft can swirl all around it and the ash can fall away.

Coal also creates a very intense spot of heat as it burns. (Think blacksmithing: coal + draft = nearly molten steel.) Modern wood stoves would be vulnerable to damage since neither the brick nor the metal below could take that intense heat.

I wouldn't consider using coal in a wood stove unless I added a couple extra layers of brick below and a heavy steel plate for the coals to sit on. I've been thinking about welding together an insert out of 1/4 inch plate steel, with a grate above. But I'm still not sure about the draft issue.

Even then, it would have to be a genuine emergency, as it would instantly void any warranty on the stove.

P.S. BobS, Congrats on your endless wood source. Nice. Free heat warms you from the inside as well as the outside.

Brangdon, how is your coal-burning fireplace set up? And how do you get it going? I have this image of a massive stone Victorian fireplace right out of Dickens. Probably all wrong. Details, please.

BTW, that reminds me of another advantage for coal: it doesn't spit out sparks like wood does.

How does the low flue tempture affect the draft. I would think that if your flue tempture is lower you would need a larger flue to get the same draw. Most of the coal fired systems I have seen here have had what seemed to be a large flue or a forced air in take.

What kind of coal would you use ? The "soft" coal we have in western PA has a high sulfer content and makes yellow smoke with a rotten egg smell. Not plesent if you live in a valley.


Ward

Good point about flue temperature. No doubt it affects the draft. Based on what I've seen in antique coal stoves, they didn't necessarily use a larger flue; rather, they used a much longer one. The long flue would hang just below the ceiling of a building (think about a one-room schoolhouse or whatever) and radiate heat all the way along.

The longer flue has the same effect: it creates a vigorous draft, even when the fuel source is getting low.

The other draft factor is "over-fire air." Many coal stoves had mechanical thermostats that would admit air above the fire to maintain the temperature output.

And sometimes, as you have noted, a forced-draft fan was used on the intake. That was a late innovation. (However, in modern times, if I have electricity I won't be pulling out the coal stove.)

BTW: The coal we have here (Alberta, Canada) is very low in sulfur. Unlike our oil - go figure. Personally, I don't mind the smell, but the first ten years of my life were in a coal-heated house. So for me it brings back pleasant memories. But as they say, YMMV.

A lot of the draft depends on the chimney geometry. The house I grew up in has a wood fireplace w/ insert that can be lit with little kindling and several sheets of newspaper. No kindling (1/4 or 1/2 logs) and more newspaper was doable. You could hear the draft once it got started.

edit:
With this set-up coal might be possible. It would need some testing for draft and burn time. A full load of wood would last about 8 hrs w/ coals left to start the next batch.

Interestingly - I've been told that coal can indeed spoil! I know a lot of folks who use coal for their large scale model trains (Look up live steam trains - I'm building one)

It seems with 'soft' coal (bituminious) there are volates that are fiven off once you mine the coal/the coal gets repeatedly wet. I understand that lignite is worse, and that the problem does NOT happen with Anthracite

That said, it supposidly only happens VERY slowly, and mostly to the top few inches of your pile - and to the surface of each lump.

According to the folks I talk to the answer is to store the coal in fairly large size lumps (say, 'lump' size), and breack it down to the 'nut', 'pea' or 'rice' size you need as you need it - and to either cover your pile with a tarp, or actually bury it!

Supposidly only a real issue for multi year - say decade storage

BTW I've lumped (Pun is intended) coal into 2 broad classes above. Lignite, Bituminious, and Anthracite (from softest to hardest). There are lots and LOTS of subgrades. When you are looking for peak performance - say you are running a power plant or steel Mill - or, on the opposite side of the size scale - the guys who run the model trains, you design your grate, flue and other parts of the system around a particular coal, and try not to switch

The Live Steam guys swear by Welch Steam Coal - but it's VERY hard to get and expensive (hey - you have to bring it in from Wales), and they USED to love Pocohantas #7 coal - but I understand #7 mine is shut, and the closest you can get is #14 (yes, different mines have different coals - so do different seams from the same mine)

This topic brought back a lot of memories from my youth when we heated our home with a couple of fireplaces and a laundry heater! For the uninitiated, a full coal scuttle is heavy when you are six and the coal pile is 50 feet from the house. It's gonna be one heck of an emergency before I want to do any heating with coal!

Anyway.........a search under "heating with coal" on Google will yield a ton of information on the topic.