+50C for an oven is very low. It feels like a slightly hot oven...
we have a device like a boiler in Russia. This is a small furnace that heats the water flowing through the batteries. Maybe that's what you mean when you talk about the stove in the kitchen?
Yes...
it's hard to live without heat in the house. Then wool and fur clothes can help out.
I don't even know what advice I can give you...
I hope the sun will be kind to you :)