Take care of heat!
After all, what is the purpose of the heating system of the building? So that it was warm in it. But it is well known that any object that heats up is radiated into the surrounding space. Therefore, in order for the house to be warm, it is not enough to make a heat source there, you still need to make sure that it is warming smaller into the atmosphere. Therefore, during the construction of the house you need to use insulation.