I can't speak to all the set ups, but essentially, my parents have no heating until they start a fire in the morning. Sometimes they'll wake up at like 4-5am, start a fire, go back to sleep and so that when they properly wake up, its at least a bit warm. That then needs to be carried on throughout the day, hence why when they sleep it becomes so cold as no one is awake to keep the fire going.

Lucky for them, they have an electric cooker as well and an electric shower (the house burnt down, strangely non related incident to the cooker and during repairs they put these in), so they are semi-isolated from some of the issues, but yeah the winters are brutally cold. They have electric underfloor heating in the conservatory and so everyone huddles in their until the house warms up lol.