Reading this thread makes me glad I live in San Francisco, where the lowest recorded temperature was 27F (4C) on Dec 11, 1932. Anything in the 40F’s is considered extremely cold for us. 
We haven’t turned on our heater in decades since putting on a sweater or sweatshirt is all we need in the winter.
Interesting idea, oil lamps that burn clear lamp oil seem pretty safe to use indoors, although I imagine it would take quite a few to heat the house. And perhaps the safety no longer applies when the exhaust is in higher concentrations due to so many lamps burning.
There will be codes to follow for the chimney pass-through to ensure the wall is properly protected from the heat, and for the height of the chimney both in total, and relative to the peak of the house, in order to ensure a good draft and prevent wind stagnation from overcoming the draft. Codes also specify hearth size and material. It takes a decent bit of research and planning to do-it-yourself, and in most or perhaps all jurisdictions also requires a permit and inspection. I would spitball a rough estimate that a basic wood stove and other materials needed would probably run in the ballpark of $2,000. I suspect hiring a contractor to do the home modifications and other work for the chimney and hearth, assuming no major complications or aesthetic embellishments would be another couple grand.
I wouldn’t recommend a woodstove just for backup heat. For that I’d consider a propane or kerosene heater (and a carbon monoxide detector). I had one installed in my home because I enjoy having a fire, I don’t mind splitting and seasoning wood, and I intended to use it for part of my normal heat, in particular when it gets cold enough my heat pump switches over to auxiliary heat. I’ve heard from plenty of other people who have stoves in their homes they almost never use because the convenience of letting the furnace do all the work is more important to them than the cost savings.
I’ve managed so far to scrounge most of my wood from trees either I or neighbors are taking down for other reasons, which increases the cost savings. I originally estimated a 10 year paypack period, but I haven’t consistently burned as much wood as my initial assumption. If I had to buy wood, the cost would be about the same as running the heat pump normally, but much less than letting it run the auxiliary heat.
Overall, it’s the combination of liking the ambiance and feel of a wood fire, the cost savings, and the emergency heat all together that made me willing to invest in a wood stove.
Overall, my reasoning for having a wood stove is a combination of savings
For power outage planning, I would say it is worthwhile to have a good idea what your goal is. There is a range of options from staying alive to maintaining your normal comfort level, with an even wider range of potential costs.
In most of the US, staying alive can be achieved by having everyone in the household share a bed and all of the blankets. In the coldest parts of the US, though, that might not be enough.
The second most important resource to me for staying warm aside from a dry roof and four solid walls is being able to heat food. A warm drink goes a long ways to helping boost your core temperature, and a warm meal significantly helps lift your spirits. I fortunately have multiple choices to help with this. My first option is a Coleman 2-burner stove for car-camping, and I can get about 2-days worth of cooking from a 1 pound propane cylinder if I am careful. I also have backpacking stove that runs on white gas, or can be converted to run on gasoline if things got really bad and I ran out of white gas. Lastly, I have a gas grill, although it’s not the best emergency cooking method. I might get a hose and adapter set to be able to connect the 20 lb propane tank I have for the grill to my Coleman stove.
The main heating resource for me is my wood stove. It’s actually a fireplace insert, and the fact that it is mostly surrounded definitely reduces the heat output. One of my planned projects is to work out a fan system for power outages. In the near term, this will probably just be based on a couple decent PC fans and a deep cycle battery. A free-standing wood stove would not really need this.
Keeping my house warm also means my refrigerator won’t stay cold. I’ve considered getting a small inverter generator, but lately I’m leaning towards getting a decent pure sine wave inverter. My Civic only burns about 1/4 gallon per hour when idling, so it should work acceptably to rely on an inverter hooked up to the car, with an extension cord to the fridge for a couple hours per day to keep the fridge at a safe temperature. So far the longest outage I’ve had in my current house was a little over 24 hours, and nothing spoiled, but the worst storms in my areas history have been decades apart, and can be as exceptional as Hurricane Sandy was for New England. Something like 25% of New England didn’t have power for at least 5 days, and I would rate my location as comparable to such areas.
Lastly, I think it should be advised with the utmost emphasis that if you use a combustion heat source inside your house, even one rated for indoor use, you should get a carbon monoxide detector. The better sealed your home is, the more important one is. It is overwhelmingly likely you won’t have any issues, but the problem is you don’t get second chances if you’re wrong. A college acquaintance of mine died from carbon monoxide poisoning due to a furnace issue. That was a sobering reminder of how insidious carbon monoxide is, and a $20 device could have saved her life.
This may be too basic for someone’s needs but supposedly one can heat up a decent sized area in a pinch with this sort of simple design. Several videos, and other articles/sites, exist that expand on the idea of the pot/candle radiant heater. Might work in an emergency. Hope this concept helps someone.
Clay pot radiant heater designs:
Yep.
The coldest temperature recorded in Palm Springs is 19F.
It rarely gets below 25F here, and with climate change, it's slowly getting a little bit warmer.
In my room, I rarely turn on the heater, and last winter, I didn't even turn on my electric blanket.
The weather here isn't nearly as mild as San Fran, but I really enjoy the mild winters here. 
They are a nostalgic collectable novelty for me but could be life saving for emergency heating. While these particular lanterns can burn a multitude of desolates, they were designed to efficiently burn kerosene at very high temperatures with minimal emissions. Knowing what to expect, I waited for a particularly cold winter night (18 F) to make this video. At approx 4000 BTU each, they quickly warmed a large cold living space. After 30 minutes, it became a bit too warm so I extinguished 5 of the 9 lanterns. The highest emissions are experienced during lighting and extinguishing, so I bring them outside during those operations. I dont recommend others to use outdoor heating appliances indoors, but I do it personally from time to time while burning high grade kerosene… and only after a complete rebuild and careful inspection of each lantern. This particular model was built like a tank and uses a large heavy cast brass burner assembly (which supports a consistent high temperature for high efficiency). Newer models use stamped sheet metal, which dont evenly heat the entire burner assembly, operate much less efficiently and are comparably untrustworthy.
Pressurized mantle lanterns like FlashPilot has are about as clean-burning and efficient as combustion-based lighting gets. There are also versions that run on white gas or on propane, which should be the cleanest in the category.
In those lanterns, pressure in the tank pushes the fuel upward in a gas generator tube that passes near the mantle. As the lantern heats up, the fuel evaporates and mixes with air as it exits the nozzle inside the mantle. This provides very well optimized conditions for clean combustion. If I understand right, the kerosene versions have to be “primed” by adding a small amount of alcohol to a cup that sits next to or wraps around the fuel tube, which you light to preheat it. I only have a little bit of experience with the white gas and propane types, but none with kerosene.
The mantle is also embedded with a mix of metal oxides that luminesce when heated, shifting more of the light from infrared to visible light compared to an open flame, so that it is more efficient at producing light.
The simpler household oil lamps or cold-blast or hot-blast lanterns produce an open flame from a wick. These kinds are less efficient at producing light. Since they rely on capillary action instead of a pressurized fuel tank, they also won’t burn fuel as quickly as the pressurized lanterns, further limiting their brightness. The cold-blast style produce a little more light than the hot-blast style, but the latter burn slightly cleaner, so they’re better for indoor use.
They still put out a modest amount of heat, though. As a rough ballpark, expect 1000-1500 BTU/hour, depending on the wick size. 3-4 such lanterns would be equivalent to a plug-in space heater. The 4,000 BTU/hour number that FlashPilot gave for his pressure lanterns is roughly equal to a plug-in space heater for each lantern.
While the pressurized mantel lanterns are the brightest and most efficient, the mantles are fairly delicate. The various wick type lanterns have their own appeal as well for their simplicity, quiet operation, and nostalgic charm. Wick lanterns are also silent, where as pressurized lanterns make a hissing noise (honestly, a comforting sound to me, but probably a distraction to some). Lastly, although pressurized mantel lanterns are brighter and provide light of a higher CCT, they seem to me to have a slight green cast. I’d like to some day verify that with a spectrometer. The wick lanterns make a very cozy, candle-like light.
Wood stove chimney is not cheap. It can easily cost more than a quality stove. Then there is the installation. But wood stoves do work. There is a learning curve. How big a home? A single stove may not heat the furthest rooms w/o power to circulate the air. Check what your insurance company would do.
It’s a larger house, around 5,000 square feet. Also the ceilings are between 12 and 19 foot ceilings depending on the room, so not a great setup for heating.
The way I started down this path is that I was shopping for generators and trying to determine the appropriate size. I average around 1500 to 2000 kWh monthly on my electric bill, but I was curious if I could get by with a smaller generator and use something more efficient for heat since generators deposit most of the energy they produce as heat outdoors. Getting some ideas from this thread that are definitely worthy of further investigation.
And I absolutely recognize this is in no way about survival, and blankets/sweaters/jackets would easily be sufficient for survival. While there is certainly a practical component, being prepared is a bit of a hobby of mine which is part of the way I ended up on this forum 
Got it. Yup, it was an interesting idea, but it doesn’t sound practical for purely emergency use. I’m perfectly satisfied with my electric heat for non-emergency use.
Great info, thanks for sharing! I also found the technology connections channel on youtube that has great videos on lanterns: https://www.youtube.com/results?search_query=technology+connections+lantern
FWIW, we have a wood burning stove, but seldom use it. It is an enameled cast iron stove selected for aesthetics as much, or more, than function. It could be used for longer term heating. We have ample split wood on hand.
We have our own solar power with a grid-tie connection but also with enough storage to power basic lighting and food refrigeration for a cloudy day, if the grid goes down. We could operate the heat pumps for heating or cooling but depending on outside temperatures not at maximum levels if too cloudy.
Is your goal to stay warm or prevent your pipes from freezing?
We are not concerned about freezing pipes as when we did a total remodel of the 50 year old home all the plumbing ended up inside the newly re-insulated shell. If we are comfortable inside, no chance of frozen plumbing. The remodel was a reconstruction in some ways. We no longer use natural gas or propane. Solar powers everything.
The grid tie connection costs about $100 for the year for the meter fee. Our PV panels produce all the electricity we need. The grid tie in effect lets us use the grid as a storage battery to draw energy from when needed. That avoids the cost of a larger battery bank.
Around my area in New England, many folks heat with wood! My father did and I also have used wood heat for the last ~50 years. I usually start the season with 6 cord of mixed well seasoned hardwood in the cellar along with an oil furnace for use in fall and spring as appropriate. The stove is in my basement and heats 3 floors including the cellar. I love having warm floors! I have propane for hot water and cooking and a generator for extended power outages. I used to cut and split my wood but at 76yo I now pay to have firewood delivered.
First I have a generator for the house. I heat my shop with wood so if I run out of gas or something I can always sleep in the shop. I have a hammock out there and take naps so it’s not that far of a push.
Growing up we heated our house with wood till I was 15. My grandparents used it till I was in my 30s. The area I live it’s not uncommon for the power to go out so we set up our houses for it. Our water heaters and stoves are gas.
Owning 90 acres it will be awhile before I run out of fuel.
Here is a propane heater that some might find useful as a blackout heater that can connect to their 20-pound BBQ tanks.
There are also other options suggested on the page.
Mr. Heater Home Jobsite 10,000 BTU Vent Free Radiant Propane Heater | MHVFRD10LP
I’m in South Florida, so if there were ever a power outage, I could just open a window. Its always hot here. I honestly think that my heater only kicks on a few days out of the year. The AC? That’s a different story.
If you lose power in July opening the window won’t help you.