We are earth sheltered, so the lowest it will get in the back rooms is about 55 degrees.
We insulated the walls between earth sheltered part of the home and the atmosphere exposed part of the home.
We have TWO propane tanks, when ONE gets empty, we call for more.
That way we ALWAYS have one tank in reserve.
We live quite a way off the beaten track, so it often takes a week for them to get here, and that is *IF* the minimum wage guy driving the truck and find the place!
If not, we wait another week to get on the schedule, and hope this driver can find his way around his hat without getting lost...
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There are some pretty efficient RADIANT propane heaters out there, and one hooked up to a PORTABLE RESERVE TANK, like a grill or fork truck tank will heat up quite an area.
You WILL have to ventilate, and if you don't already have a carbon monoxide detector with battery back up, and you have propane heat, there is something wrong with you!
I have a propane radiant that attaches right to the top of the tank and will heat any given room to a comfortable temp.
Great to have an extra tank and that heater in reserve!
Radiant heaters are MUCH LOWER EMISSIONS than something like an open flame grill, which WILL kill you in short order!
I sometimes use kerosene heaters in the shop.
Kerosene is MESSY to use, stinks, but gives pretty good heat.
MUST BE VENTILATED!
Kerosene makes a Lot of carbon monoxide, so ventilation and carbon monoxide detector is required.
I prefer propane, but Kerosene is my 'Back Up' and stores pretty well.
I know you can't do this as are retrofit, but radiant floor heat is a good thing.
Cost us about $350 for a wood/coal/corn fired boiler as a back up when we installed the radiant floor heat.
Takes about an hour to get the backup boiler fired up, making heat, and get the valves/pumps switched over (Solar/Batteries, we are never without electricity) for the boiler to start working if something happens with the propane/electric boiler...
Something to consider if you go 'Off Grid' or build from 'Scratch',
Nothing quite as flexible, or quite as comforting as radiant floor heat,
And it's SUPER efficient to boot!
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To stop what happened to you from happening again,
INSULATE THE CRAP OUT OF THE OUTER WALLS AND THE CEILING/ROOF!
Keeping heat in, even foundation or basement heat will keep pipes from freezing, and keep more of your hard paid for heat generation from leaking out!
Remember, the heat as to go somewhere for cold to creep in!
So fill those cracks, and insulate!
Consider a 'Secondary' heat source,
Not to heat the home to a 'Comfortable' level, but make it 'Livable' with some blankets/sweaters.
Kerosene heaters are a pain, they stink, they are dangerous, but they WILL keep the pipes from freezing and your nose from forming 'Snotsicles' (snot Popsicle)!
Propane grill tanks and radiant heaters will do the same, but you don't get the same BTUs/Heating time from the storage space.
On the other hand, Propane is useful for a number of things, doesn't go bad in storage, and is SAFER to store than Kerosene.
I use it for the grill, for cutting gas in the shop, for 'Camp Lights' and 'Camp Heat', and I have a propane powered vehicle (also burns gasoline, dual fuel).