While there are no direct uses involving DC power equipment and heating in a self reliant situation, we include some information on the subject, as it might be useful. Using battery storage, for example, to run a resistance heating device, is very inefficient. Other options are much more advisable, so your battery storage can be used for other things. Battery backup is appropriate for the augers used in pellet stoves, so they can run during power outages.
Heating without electricity can be done with a variety of fuels, some of which you may already have and use. This includes propane, natural gas, coal, wood, kerosene, heating oil, etc. You can get one and two burner heaters that attach to the 5 gallon (20 pound) and larger propane tanks that also work with the propane barbeque. You wouldn't try to heat the whole house this way, but a room or two is no problem. Apartment dwellers are generally confined to this setup. If you have natural gas and a natural gas heater that doesn't use electricity for a fan or controls, it should work as long as the gas distribution system functions. Coal stoves work fine, just are dirtier and involve some more maintenance than others. You can, however, bury several tons of coal in your yard for use down the line (if you can get the coal delivered). Kerosene heaters have been used for a long time. You can get a decent heater and a spare wick or two, and store kerosene in one or 5 gallon containers, or even a 55 gallon drum. See the fuel storage section. Heating oil fired heaters are frequently used. Some require electricity for operation, but some don't, they only gravity feed. Heating oil (same as diesel) can be stabilized for long term storage (see fuel storage section). They also can be used to burn waste oil, if properly filtered.
We put wood heating by itself for a variety of reasons: the fuel stores well, is renewable, can be gathered if necessary, and most of the devices (stoves) that burn it lend themselves well to cooking or heating water. These can be the primary heating for the home, or auxilliary heating sources if you have a heat pump or other heat source. Pellet stoves are limited, in that you can't easily make your own pellets. You can store them, however. Also, you can burn wood in a pellet stove if necessary.
Everybody needs some sort of heating facility, unless you have a purpose built solar house in the south or southwest part of the country. Apartment dwellers may be limited to propane type heaters, or kerosene, but fuel storage may be an issue for kerosene. If you are rural, semi-rural, or country, you have more options that may already be a part of your life. If you have a wood stove, be sure you have the equipment to also use the stove for cooking, and always keep two years of wood put up.