hyway61 wrote:In Europe they are called brown brick coal
I think bio-bricks are MODELED on the brick coal used in Europe, but are compressed wood chips and sawdust, not coal. I burned about one and a half tons of them two winters ago, in a Russo catalytic wood stove.
You have to follow instructions and stack them close together to avoid too-fast a burn. Also don't try to use them unless your stove is air-tight and controllable, as you can get a run-away fire more easily than with logs. I didn't have any run-aways, but I could see the tendency was there. There's a "technique" to burning them, basically rake your coals to one side or to the front, and stack the bricks so they burn from one side to the other like a cigar, rather than all together. (Though a couple hours after reloading you will probably have the whole mass burning.)
If I stuffed the stove with bricks I could get about the same length of burn as a full load of wood. One thing I didn't like: when the fire was burned almost out, the remaining "coals" were low density compared to regular wood coals, so you couldn't just stir up the coals and throw on substantial chunks of wood or bricks to get the fire going again; more likely you had to throw on some kindling and nurse it for awhile. And tossing a few more bricks onto a burning pile tended to disrupt the burn because of the lower density of the half-burned bricks -- they might just collapse and scatter. Overall, the bio-bricks required more attention than wood and were not quite as flexible because of the stacking and density issues.
Definitely neater and cleaner to store and handle, and lots less work than burning cord wood. Creosote and ash were comparable to burning dry wood, no better, no worse. The same smoke enveloping the house and the neighbors' houses on rainy nights. The same up-and-down, hot-and-then-cold problem as with regular firewood. The same problem of getting up at 3 am to replenish the fire so it wouldn't be dead by morning, though the bricks needed more time and attention to replenish compared to wood, as described above. $300 per ton here in Maine, though that may decrease if we get a couple local plants producing them and cut out some of the transportation cost. So all in all, bio-bricks are a viable but not ideal alternative to firewood if you weigh the extra $$$ against all the labor of firewood.