1. Wear long underwear.
2. At night, and on cold days, fill a hot water bottle with very hot water, wrap it in a towel and put your feet on it.
3. For people with respiratory issues an unvented kerosene heater will increase their susceptibility to colds and other respiratory ailments.
4. The Germans, a generation ago, would only heat one room in the house.
5. Think camping out indoors. The tent in the living room works well if you have several blankets under you with hot water bottles near your feet.
6. With all the regulations you may not be able to do much with wood stoves, pellet stoves and the like. An electric oil filled radiator style heater would be quite effective in a tent. Outside the tent use lap blankets, hot water bottles, and long underwear.