How warm is your house with no heating? Not every house is the same.
Personally I go for merino wool thermal base layers, woolly jumper fleece, snood/cowl, hat/hoodie and fingerless gloves/wrist warmers, warm socks. Slippers when walking about or feet on floor sitting.
Woolly blankets, duvets on the sofa.
Ds on the other hand is in shorts and t shirt. 
I've got gel hand warmers for emergency. You can get battery powered heated jackets.
Cooking :BBQ outdoors. Or Kelly kettle. If you have somewhere outdoors to store it a camping stove and gas bottles. You could warm water and put in flasks. Food flasks for soup/noodles/cous cous
Light from solar lanterns and battery lanterns.
Power banks. ( Bog standard Asda ones)
My mum's house would require a tent in one room as it is less well insulated.
I run cold. Ds runs hot.
Long term. Insulate your house. Loft insulation, including the hatch. Thick curtains. Draught excluders.