I'm not sure if my solution will help but I'll share anyway. Last winter we heated with underfloor electric
. While, it did keep us warm down to -46C (-51F), which was the lowest night last winter, it cost us a fortune in electric bills. Our highest monthly bill was $460 for electricity, whereas it's $30 in Summer. So we looked for a cheaper solution for this coming winter.
We came up with a central heating system based on semi-coke briquette boiler feeding radiators in each 'ger' (Mongolian word for yurt) plus the bathroom, insulated shipping container and well house. 5 radiators total. We'll fit TRV (thermostatic radiator valves) soon. The whole 'open' system is filled with anti-freeze so it can't freeze until about -40C/F. Open systems allow simple expansion of the anti-freeze too.
We chose semi-coke briquettes as our fuel source because this is the only coal product that is legal in Mongolia now. They are also subsidized and rationed. We are allowed 7 bags a week (a bag is 25kg / 55lb) and it's sufficient. The advantage over wood is that it's much cheaper and will burn 12-16 hours without attention which is what we need in a Mongolian winter. Did I mention it's cheap? Yes, it's $1 per bag or about $40 per metric ton (2200 lbs). Our heating season is mid-September to mid-May.
Here are some pics.
Furnace room in a shipping container in the back of the 2 (Siamese) gers, connected with a bathroom.
Pipes go underground (about 2m) then enter the bathroom, steel insulated panel construction.
The living room 'ger' radiator. The bedroom is the same size. Our gers are 40m/2 (about 430sq ft). The bathroom and well house radiators are half this size.
Thermostatic radiator valves control the temperature of each radiator. Some of them are just needed for "frostproofing", like our shipping container and well house.
We made an insulated, partitioned furnace room in one of our shipping containers. The pipes are insulated and go underground between the shipping container and the bathroom, then to each 'ger'. Another branch goes to the well house (about 30m away).
It was a bit of pain in the wallet to pay for a 2nd system when we'd already paid for underfloor heating but we should break even on the new system in the 2nd winter on electricity savings alone. It's Mongolia so it wasn't expensive by Western standards. About $3k installed. It's hard to put a price on staying warm in winter, especially when you
would die without it.
I'm not sure how this would apply to the OP's situation. Maybe just anti-freeze would work? Or underfloor electric heating.
is very important but I can't say our 'gers' our very insulated by house standards with just 5-7cm (2-3") of wool felt. A lot of people with a single ger and no extra buildings just use a stove. A dual-use wood/coal stove is very nice but might not suit airb'n'b if you're not onsite.