Wow that was pretty.. unhelpful. Seal up your house real good and now light a fire. Dress warm . Anything else captain obvious? And getting in a car? You mean the big largely uninsulated metal box with air flowing on all sides?

1) decide what space you are going to heat and hang sheets if needed to block off that space. ( yes a tent WILL work, and may be a good idea for sleeping.. but most tents people have won't allow you to stand up. If you have one - fine., but a sheet is surprisingly good at blocking air flow and therefore heat lost.

2) a traditional indoor wood stove is ideal, but failing that a small rocket cooking stove ( runs on twigs) would be better than candles. Or larger rocket stoves are easy to create with barrels or trashcans. Just Make sure you have a way to exhaust the smoke. Candles aren't going to cut it

3) People. People produce heat. The more people you have in a space, the warmer it will get. If you really can't stay warm get a bunch of people together. - Sure you can go to the Government approved "warming spaces" - Just hope no one poisons your food or water or rapes you ...

4) Get Solar electricity Yes it can be expensive. But an inverter all by itself will put off heat all day why it is operating ( I use my inverter exhaust to heat a greenhouse in the winter - and then shut it out another way in the summer) Plus you can generate actual electricity that you can use for pumping water and other tasks - or run your furnace.. The solar heaters they are talking about can be made with a couple sheets of plexiglass, a bunch of aluminum cans and some black paint. You just need a channel through the wall at the top and bottom that allows air to enter, get heated up by the sun and the hot cans and re-enter the home near the top. I passively heat my shop this way.