Masonry Heater for my Yurt

[hierony]

So winter is coming. I've been

heating

with electricity & a propane space heater, but that gets expensive. The propane isn't vented, which is not great (I've a CO monitor though, & have measured CO with a Fluke meter--no carbon monoxide produced; don't want to run it overnight though). Wood is readily available in my area, very cheap if you do all the work & not too expensive if you only do some of the work (getting logs out of woods, cutting into rounds, quartering, stacking, etc), and is renewable & carbon neutral.

Because yurts aren't terribly well insulated or air-tight & have little thermal mass, I don't think standard wood stoves are a good match for

heating

a yurt. They'll easily heat the yurt when running, but things will get cold pretty fast when you aren't burning anymore. From the sounds of other's experience, it's hit or miss whether you can get your stove to put out enough heat overnight without stoking it halfway through. I've already noticed with the propane heater that though it increases the air temp quickly, all the mass takes a while to warm up (ie, the bed).

So I decided to go with a masonry heater. It has a small footprint (~30x30 inches), should burn very clean & efficiently, will heat continuously so there won't be cold/hot cycles & all the yurt mass will be warm (not just the air). Plus it won't present a burn hazard for people or pets. Cost is around $1k ($200 design fee, $350 firebrick/facing bricks, ~$300 door/ports/refractory cement/misc materials, plus chimney).

I have a strawbale platform & the heater will be heavy, so I had to do something a little different for the foundation under the heater in the middle of the yurt. I didn't put straw bales there. Instead, a layer of leveling sand, cinder blocks to distribute the load & match the wood platform level, a sheet of steel to distribute contact point loads, then a reinforced lightweight-aggregate concrete (perlite & expanded shale), then 1/2" cement board. The cinderblocks can carry quite the load, & everything else will do great in compression & is _not_ burnable.