To start with, I am going to have in totall 4 different heat sources to choose from for different occasions and times of the year. I know it sounds kinda crazy for such a small house, but I really hate being cold. I have installed two 15,000 BTU propane heaters. They are both direct vent type heaters meaning that they bring in combustion air from out side and send the exhaust to the outside. IMPORTANT! I'm not a pro at this stuff, but I do know that propane appliances might not be allowed in basements in all areas. You will have to check with your local permitting offices I guess. (Propane is heavier than natural gas and will pool at the bottom and could fill a basement and create quite an explosion if ignited, whereas natural gas may dissepate more easily out the windows and doors etc). They're both dangerous as far as I am concerned.
I chose to go with the two smaller heaters instead of one 30,000 BTU one, because with the lower BTU, they can be installed in alot of different tighter spaces. (Closer to a corner, closer to window, mounted up higher on the wall etc). Also a bigger heater was kind of hard to find with a direct vent that would work in a basement. A bigger heater would have meant running another chimney (B vent). It's a long way to the top from the basement, and chimneys take up more of my space. Also, the B-vent type chimney requires me to bring in outside air for combustion, which makes me feel as though I am defeating my purpose a bit. Although, I might have to do that for my wood stove, but I'm not real sure yet, I may be able to modify it to a direct intake.
Anything water is all at one end of the house, whether it be up stairs or down. Most anything that I need to worry about is in the basement, but upstairs will be a kitchen sink that is practically right over top of one heater, and on the other side is the bathroom vanity and toilet over the other heater. I'm pretty confident that I would be able to leave the house for days without worry in the colder winter days. However, if it is -40 outside for a prolonged period, I find from experience in my shack that these type heaters probably are'nt going to put out as much as they should. Propane movement really slows down. At -42 I think it is, propane no longer vapourizes, so I sure hope that it don't get that cold for very long if I'm not around. However with a 1000 gallon tank that I now have will be alot better than the 100 pound tanks that I used to use. I will top up the big propane tank once every summer so that has a good percentage of product for the winter.
If I were to leave for a month or so, I would winterize the house something like you would do to your RV. Draining everything that should be drained and run plumbing antifreeze through all the lines etc.
I plan on experimenting with all my different sources of heat to find what works best for different situations. I think if I stoked the wood stove and turned it down before leaving the house that the forced air furnace will be able to keep things warm for a couple days after the fire burned down, without charging the batteries. However, this all depending on how often the furnace cycles, but I know this house is very well insulated and I'm thinking it will hold it's own heat for a long time on average temperature days. But if the sun is shining and there is'nt a big amount of snow on the solar panels, it would probably be able to keep the house warm, as this would be the only electrical power being used while I am gone. The MPPT charge controller that I have installed in my electrical system is supposed to really shine in the colder weather. If my batteries will run the furnace, this would be the most economical heat source, but if the battery voltage goes down to my preset voltage then the inverter will shut down until a preset voltage is present again.
Eventually I may be installing some kind of AGS(Automatic Generator Start), but I will experiment with what I have first.
Then when all else fails and the furnace does not want to run, the two space heaters in the basement should kick in and hopefully do their thing.
The photo below shows one of the two propane heaters on the right.
The above photo is a quick drawing of the the Basement and Main floor plans to show the location of heat sources lined up with vulnerable water areas. The two space heaters are drawn in red. As a comparison, the direct vent heater in my shack is 22,000 BTU. I have slept in the shack when it was -35-40. It was'nt too bad in the top bunk, but I have had pop cans explode in the middle of the night. They were sitting on the floor. lol. The shack is'nt real well insulated and is built with only 2x4 walls.
When I am at home, it will not even be a chore to stoke the fire. I say bring on the cold.
As for the water cistern outside, I am really hoping the water don't freeze up too badly in there. I do expect to see a thin layer of ice develope on the surface of the water at times, but hopefully it won't be a problem. I do have an insulated lid on it, and I will bank snow around the top part of it sticking out of the ground. There was about 2 feet of water in it all last winter. I checked it in the early spring and seen no ice. That could possibly be the solution is to not fill it right up to the top. There is heat that comes from the ground and the water way down there does'nt seem to freeze. The cistern is about 11 feet deep and 8 foot diameter. With this diameter of pipe, I was told that for every meter of pipe you will hold 995 gallons of water. Half full would be about 1500 gallons, and that is alot for me. I don't think I would have to worry about it freezing if kept it at around this level.
I had no heat in my house all last winter, and the sump in the basement had about an inch of water in it. I had some insulation over top the sump and that inch of water did not freeze all winter either. It was a fairly mild winter if compared to some, but it was still pretty chilly at times.
This is what my plan is for things, but that does'nt necessarily make it the right way to do things. I am not a pro, and I am also learning as I go. I guess time will tell if it's all going to work for me, but I do expect to be doing modifications on things as I go if need be. I'll be alot smarter after the next winter hopefully.